F-Gas English Low GWP
Všetky otázky
HFC | Flammable | CO₂ | NH₃
Ľahké otázky |
Stredne ťažké otázky |
Ťažké otázky
1
Stredne ťažká
What process takes place in the condenser of a refrigeration system?
| The refrigerant releases the heat absorbed in the compressor via the condenser |
| The medium flowing through the evaporator (glycol, water) condenses, whilst the refrigerant evaporates. |
| Hot refrigerant vapour is pumped from the compressor to the condenser, where it is cooled and then condensed. In this heat exchanger, the resulting liquid refrigerant is also slightly subcooled. |
| In the condenser, the refrigerant releases the heat absorbed in the evaporator into the surroundings. |
2
Stredne ťažká
What determines the condensation temperature of an air-cooled unit?
| On the ambient temperature. |
| On the compressor and discharge temperatures |
| On the evaporation (boiling) temperature. |
| On the superheat temperature. |
3
Stredne ťažká
Is energy required when heat is transferred from the condenser to the surroundings?
| No, because according to the second law of thermodynamics, thermal energy always flows from a body at a higher temperature to a body at a lower temperature. |
| The heat flow balances the energy input. |
| Yes, but only when using HFC refrigerants. |
| Yes, in every case. |
4
Stredne ťažká
What should you pay attention to during the operation of the condenser?
| Care should be taken to ensure that the air temperature at the condenser inlet is lower than the air temperature at the condenser outlet. |
| Pay attention to the fan’s operation and the ambient temperature. |
| You should ensure the general maintenance of the condenser and keep the heat exchange surfaces clean. |
| Ensure that the air temperature at the condenser outlet is higher than the condensation temperature. |
5
Stredne ťažká
What criteria should be considered when selecting a suitable condenser?
| Condensers should be selected based on your own experience, and the condenser’s geometric parameters should be taken into account. |
| These include size and the number of fans. The geometric parameters of the condenser must be taken into account. |
| The required capacity of the condenser and the technical specifications declared by the manufacturer must be taken into account. |
| First and foremost, you should consider the operating noise level of the fans, the diameter of the connection pipes and the colour scheme. |
6
Stredne ťažká
How do contaminants (dust, particulates, deposits) affect the performance and efficiency of heat exchange surfaces in condensers?
| Contaminants increase the heat transfer area and reduce the condensing pressure. |
| Contaminants restrict heat transfer (reducing the heat transfer coefficient) and cause a reduction in condensing pressure. |
| Contaminants restrict heat transfer (reducing the heat transfer coefficient) and cause an increase in condensing temperature and pressure, which in turn leads to a reduction in the condenser’s efficiency. |
| Contaminants do not significantly affect the efficiency and effectiveness of the heat exchange surfaces in condensers. |
7
Stredne ťažká
If an air-cooled condenser becomes contaminated, will the condensation efficiency?
| It remains unchanged. |
| It will increase as a result of the fan speed being raised further. |
| It will decrease. |
| It will increase. |
8
Stredne ťažká
What can cause frost to form on the evaporator?
| An increase in refrigerant flow resistance and a reduction in the refrigerant flow rate through the evaporator. |
| Frost build-up on the evaporator increases airflow resistance and, consequently, causes the fan motor to work harder. |
| a drop in cooling capacity. |
| A reduction in the temperature of the cooled substance. |
9
Stredne ťažká
What happens when the evaporation temperature drops?
| The condenser fan speed increases. |
| The compressor’s cooling capacity decreases. |
| The compressor’s cooling capacity increases. |
| The discharge temperature decreases. |
10
Stredne ťažká
When is defrosting using the refrigerant possible?
| Only when using speed-controlled fans. |
| In the case of air-cooled chillers, only when the air temperature is above 0°C. |
| Defrosting using the refrigerant is not possible at all. |
| Never. We use electricity for defrosting (for example, using a special electric heater). |
11
Stredne ťažká
When can frost form on the evaporator surface?
| In the case of finned evaporators. |
| Frost forms only when the refrigeration system is operating continuously. |
| Frost always forms on air coolers. |
| Only in the case of air coolers, when the air temperature drops below 0°C. |
12
Stredne ťažká
In the case of extensive pipework systems, secondary evaporation of the refrigerant can be prevented by...
| by insulating the pipes between the compressor and the condenser. |
| additional cooling. |
| using larger-diameter pipes. |
| using smaller-diameter pipes. |
13
Stredne ťažká
How does hot gas defrosting of the evaporator work?
| Heated vapour (hot gas) from the compressor is directed into the evaporator piping. |
| We swap the outlet and inlet sides of the evaporator. |
| We switch on the gas heater directed at the evaporator. |
| This involves reversing the direction of rotation of the compressor. |
14
Stredne ťažká
What is the function of the evaporator in a refrigeration system?
| It cools the refrigerant. |
| Thanks to the evaporator, the cooled medium transfers heat to the boiling refrigerant. |
| It ensures that the refrigerant is superheated over the largest possible heat exchange surface area. |
| It evaporates the water flowing through the evaporator. |
15
Stredne ťažká
What conditions must be met for the evaporator to be defrosted using electric heaters?
| The electric heaters must be positioned in direct contact with the refrigerant so that the refrigerant flowing through the evaporator is at a sufficiently high temperature. |
| The electric heaters must be positioned beneath the evaporator’s heat exchange surface. |
| The electric heaters must be in contact with the evaporator’s heat exchange surface (the heater must touch the fins). |
| Thanks to the forced air flow created by the fans, the heat from the heaters is transferred to the heat exchanger. |
16
Stredne ťažká
Refrigerant distributor:
| acts as a buffer for the refrigerant in the event that the pressure upstream of the expansion valve is exceeded. |
| ensures even distribution of the refrigerant to the individual sections of the condenser. |
| ensures an even distribution of the refrigerant to the individual sections of the evaporator. |
| ensures the even distribution of the refrigerant discharged by compressors connected in parallel. |
17
Stredne ťažká
What are the possible methods of defrosting air coolers?
| Electric defrosting, liquid defrosting or defrosting using hot refrigerant vapour. |
| Natural defrosting; there are no other effective methods. |
| Hot gas defrosting. |
| Electric defrosting only. |
18
Stredne ťažká
The boiling point increases (and consequently the rate of evaporation increases) if the pressure above the liquid...
| Remains constant. |
| It behaves differently depending on the ambient temperature. |
| Falls. |
| Rises. |
19
Stredne ťažká
MOP in thermostatic expansion valves stands for:
| minimum flow opening. |
| self-cleaning of the valve in the event of moisture in the refrigerant freezing. |
| maximum pressure switch protection. |
| maximum operating pressure. |
20
Stredne ťažká
The function of a thermostatic expansion valve (TEV) in a refrigeration system is:
| regulating the superheat of the refrigerant leaving the evaporator so that it is at the minimum value. |
| to consistently adjust the evaporation pressure in the condenser depending on the temperature of the refrigerant vapour leaving the condenser. |
| to control the amount of refrigerant supplied to the evaporator depending on the superheat of the vapour leaving that heat exchanger. |
| to maintain a constant suction pressure to the compressor. |
21
Stredne ťažká
When using a capillary tube, what type of motor can be used in the compressor?
| A low-speed motor should be used. |
| A motor with high starting torque must be used. |
| A motor with low starting torque can be used. |
| An electronically commutated motor approved for use with the compressor should be used. |
22
Stredne ťažká
What does the thermostatic expansion valve regulate?
| The mass flow of the refrigerant injected into the evaporator. |
| Discharge temperature. |
| Evaporation pressure after. |
| Cooling. |
23
Stredne ťažká
The refrigerant absorbs heat when...
| it condenses. |
| freezes. |
| it evaporates. |
| sublimates |
24
Stredne ťažká
In the case of a thermostatic expansion valve, the manufacturer specifies...
| ...the degree to which the valve is filled with refrigerant liquid. |
| ...the superheat value during valve operation. |
| ...the static superheat of the valve. |
| …the degree of refrigerant expansion. |
25
Stredne ťažká
How do we charge a new or repaired system with refrigerant when it is fitted with an expansion valve
| in any way. |
| behind the condenser to the liquid refrigerant receiver. |
| Charging with refrigerant takes place during operation via the outlet connection of the refrigerant capillary tube. |
| to the suction side of the compressor. |
26
Stredne ťažká
What does a thermostatic/electronic expansion valve regulate?
| The evaporation pressure, closing when it falls below the setpoint temperature. |
| The number of revolutions of the compressor per unit of time. |
| Condenser subcooling by adjusting the condensing pressure. |
| The amount of refrigerant by controlling the evaporator superheat. |
27
Stredne ťažká
What does the MOP function in expansion valves mean?
| It means that these expansion valves are set to limit the maximum operating pressure. |
| This means that these expansion valves are set to a specific suction pressure. |
| This means that these expansion valves are set to prevent overheating. |
| This means that these expansion valves are set to limit subcooling. |
28
Stredne ťažká
The lower the temperature of the liquid refrigerant upstream of the expansion valve,
| ...the lower the theoretical coefficient of cooling efficiency qo will be, whilst the cooling capacity Qo remains unchanged. |
| ...the lower the theoretical coefficient of refrigeration efficiency qo will be, and the lower the refrigeration capacity Qo will be. |
| ... the higher the theoretical coefficient of cooling capacity qo will be, and the greater the cooling capacity Qo will be. |
| ...the lower the theoretical coefficient of cooling efficiency qo will be, and the lower the system’s energy efficiency will be. |
29
Stredne ťažká
The MOP point in the expansion valve, due to the maximum evaporation temperature of the refrigeration system, ...
| ...must be approximately 5 K lower. |
| ...must be approximately 7 K higher. |
| The value of the MOP point is irrelevant. |
| ...must be approximately 7 K lower. |
30
Stredne ťažká
What is the function of the suction pressure regulator?
| It limits the suction pressure and protects the compressor from excessively high suction pressure. |
| It maintains the suction pressure at a constant level. |
| To maintain the suction pressure at the highest possible level. |
| It prevents a drop in suction pressure and, if necessary, shuts down the refrigeration system. |
31
Stredne ťažká
What is the function of the valve regulating water flow through the condenser?
| To maintain the condensing pressure at the lowest possible level. |
| To maintain the condensing pressure at the highest possible level. |
| To maintain the condensing pressure at a constant level. |
| To maintain the water temperature at the highest level. |
32
Stredne ťažká
The use of a refrigerant distributor requires a thermostatic expansion valve …
| … with a MOP function. |
| … with internal pressure equalisation. |
| … with an adsorption-type sensor filling. |
| … with external pressure equalisation. |
33
Stredne ťažká
What properties should good insulation materials have?
| It must have a low thermal conductivity. |
| It must have a good antistatic coating |
| It must be able to absorb large amounts of moisture. |
| It must have a high thermal conductivity. |
34
Stredne ťažká
When do we encounter the superheated state?
| This is a state that arises as a result of the temperature difference between the suction side and the discharge side of a compressor. |
| It is a condition in which the compressor motor temperature rises excessively. |
| This is the temperature difference between the actual vapour temperature and the vapour temperature at saturation. |
| It is the temperature difference between the evaporation temperature and the ambient temperature. |
35
Stredne ťažká
How can you check whether the liquid refrigerant is reaching the expansion valve without vapour bubbles?
| We check this using a sight glass. |
| We check using a liquid pressure gauge. |
| We check using a pressure gauge fitted on the discharge side of the compressor. |
| We are unable to check this. |
36
Stredne ťažká
The liquid lines are located...
| between the compressor and the condenser. |
| between the evaporator and the compressor. |
| between the evaporator and the regenerative heat exchanger. |
| between the condenser and the liquid receiver. |
37
Stredne ťažká
What is the function of the liquid receiver in a refrigeration system?
| The reservoir is used to further cool the liquefied refrigerant leaving the condenser. |
| The tank is used to store and ensure an adequate supply of refrigerant in the event of fluctuations in the thermal load of the refrigeration system. |
| The tank is used to collect the liquid refrigerant and excess oil in the system. |
| When an installation technician does not know the exact amount of refrigerant required, the tank serves as a safety reserve for the entire refrigeration system. |
38
Stredne ťažká
What is the purpose of the liquid refrigerant reservoir?
| The tank is used to further cool the liquefied refrigerant leaving the condenser. |
| When an installation technician does not know the exact amount of refrigerant required, the tank serves as a safety reserve for the entire refrigeration system. |
| The tank is used to collect the liquid refrigerant and excess oil in the system. |
| The tank is required during maintenance work, when there is a temporary need to store the refrigerant that has been circulating in the refrigeration system up to that point. |
39
Stredne ťažká
Where should the liquid receiver be installed?
| It should be fitted just before the compressor. |
| It should be installed downstream of the condenser, upstream of the expansion valve. |
| It should be fitted between the compressor and the condenser. |
| It should be fitted after the evaporator. |
40
Stredne ťažká
What is the function of the suction pressure regulator fitted to the suction pipe when the compressor starts up?
| It opens when the suction pressure upstream of the compressor drops. |
| It regulates the condensing pressure. |
| It regulates the evaporation pressure. |
| It closes when the suction pressure upstream of the compressor drops. |
41
Stredne ťažká
The use of microchannel heat exchangers, compared with conventional heat exchangers made of copper tubes and fins, results in:
| There is no effect whatsoever on either the amount of refrigerant or energy efficiency. |
| An increase in the amount of refrigerant in the system and an increase in condensing pressure. |
| A reduction in the system’s energy efficiency. |
| A reduction in the amount of refrigerant and an increase in energy efficiency. |
42
Stredne ťažká
Which refrigerants belong to the HFC group?
| R134a, R404A, R507A, R410A. |
| R22, R401A. |
| R11, R12, R502. |
| R134a, R32, R22, R507A, R290. |
43
Stredne ťažká
Which refrigerants belong to the HFO group?
| R1234yf, R1234ze. |
| R22, R12. |
| R134a, R404A. |
| R134a, R290. |
44
Stredne ťažká
What are the characteristics of R410A refrigerant compared to R407C refrigerant?
| The saturation pressure of R407C is 150% higher than that of R410A. |
| The saturation pressure of R407C refrigerant is much higher than that of R410A. |
| The saturation pressure of R410A refrigerant is higher than that of R407C. |
| The saturation pressure of both refrigerants is roughly the same. |
45
Stredne ťažká
What does the TEWI parameter define?
| It is the total (global) greenhouse gas equivalent – this indicator takes into account the refrigerant’s direct capacity to contribute to the greenhouse effect and its indirect impact on it through the energy consumption (during the production of which CO₂ is generated) by the refrigeration unit in operation. |
| It is the global warming potential, expressed in terms of carbon dioxide (CO₂), over a 100-year time horizon. |
| This is a parameter that quantifies the impact of refrigerants on the ozone layer. |
| This is a parameter defining the ozone layer’s ability to recover (regenerate). |
46
Stredne ťažká
What are the characteristics of R452A refrigerant compared to R404A?
| Both refrigerants are homogeneous refrigerants with no temperature glide. |
| It is a non-flammable refrigerant, a mixture from the HFC/HFO group with thermodynamic properties similar to those of R404A and a GWP approximately 45% lower than that of R404A. |
| The temperature glide of R452A is half that of R404A. |
| It is a flammable and toxic homogeneous refrigerant from the HFC group. |
47
Stredne ťažká
What is the distinguishing feature of R1234yf compared to R134a?
| A higher critical temperature. |
| greater flammability. |
| greater toxicity. |
| a higher boiling point at standard pressure. |
48
Stredne ťažká
Compared to R134a, the refrigerant CO₂ is characterised by?
| It has a lower critical temperature, higher operating pressures and greater volumetric efficiency, allowing for the use of a smaller quantity of refrigerant compared to R134a. |
| Unlike R134a, it is an azeotropic mixture. |
| It has a temperature slip of 7K greater than R134a. |
| It has identical thermodynamic properties and can be used as a drop-in replacement for R134a. |
49
Stredne ťažká
The following are not classified as fluorinated greenhouse gases:
| Carbon dioxide (CO₂). |
| Perfluorocarbons (PFCs). |
| Hydrofluorocarbons (HFCs). |
| Sulphur hexafluoride (SF6). |
50
Stredne ťažká
What is the greenhouse effect?
| It causes the thermal radiation emitted by the Earth to be trapped in the upper atmosphere. |
| It lowers the average surface temperature of the Earth. |
| It causes an increase in temperature close to the Earth’s surface (up to 10 metres above the surface). |
| It alters the composition of the atmospheric air. |
51
Stredne ťažká
How do refrigeration systems contribute to the greenhouse effect, i.e. the rise in atmospheric temperature at the Earth’s surface?
| Indirectly (through energy consumption) and directly (through the emission of refrigerants into the atmosphere) |
| As a result of oil being emitted into the atmosphere by the condenser and filter |
| Refrigeration equipment emits CO₂ both directly and indirectly. |
| Through the leakage of refrigerant into the environment. |
52
Stredne ťažká
What is the greenhouse effect, also known as the greenhouse phenomenon?
| The absorption of radiation reaching the Earth’s surface. |
| This is the formation of a layer that traps only the heat generated by the combustion of fuel in aeroplanes. |
| It is the phenomenon of heat being trapped in the Earth’s atmosphere (making it difficult for heat to radiate out of the Earth’s atmosphere). |
| The filtering out of solar radiation. |
53
Stredne ťažká
Which EU regulation is currently the primary piece of legislation governing the use of fluorinated greenhouse gases (F-gases) in the European Union?
| Regulation (EU) No 517/2014 |
| Directive 2009/125/EC |
| Regulation (EU) 2015/1188 |
| Regulation (EU) 2024/573 |
54
Stredne ťažká
What is the main objective of Regulation (EU) 2024/573?
| Prevention of F-gas emissions and the achievement of the EU’s climate targets |
| To reduce taxes on refrigeration equipment |
| Standardising metal recycling standards |
| To facilitate the import of electrical appliances |
55
Stredne ťažká
What are the obligations of manufacturers of refrigeration appliances in the context of ecodesign, and which regulation governs them?
| Manufacturers must comply solely with ISO 9001 standards, without any link to EU regulations |
| Manufacturers are only required to declare the quantity of F-gas used, in accordance with Regulation (EU) No 517/2014 |
| Manufacturers are only required to use energy labels, and this is regulated by Regulation (EU) 2024/573 |
| The manufacturer must ensure minimum energy efficiency, reparability and recyclability of equipment, as regulated by Regulation (EU) 2019/2019 |
56
Stredne ťažká
What is the main objective of the Ecodesign Directive?
| Reducing the negative environmental impact of products by improving energy efficiency, durability and recyclability |
| To facilitate the import of products from outside the EU |
| To standardise the appearance of products in the EU |
| To increase sales of electrical appliances in the EU |
57
Stredne ťažká
What is the function of a ball valve in a refrigeration system?
| Enables the refrigerant flow to be completely shut off |
| It regulates the temperature of the refrigerant |
| It prevents excessive pressure build-up in the system |
| It measures the moisture content of the refrigerant |
58
Stredne ťažká
How do certain substances or gases contribute to the greenhouse effect?
| Certain substances limit the impact of the Sun’s ultraviolet radiation on the Earth’s surface. |
| Some substances damage the ozone layer |
| When released into the atmosphere, certain substances cause the air to heat up as a result of reactions with the oxygen and nitrogen contained in the air. |
| Certain substances trap the thermal radiation that the Earth should radiate into the atmosphere. In this way, the Earth gradually warms up and the greenhouse effect occurs. |
59
Stredne ťažká
What is the purpose of the sight glass in a refrigeration system?
| To shut off the flow in the event of an emergency |
| To measure the condenser temperature |
| For visual assessment of the presence of refrigerant and oil, and for monitoring moisture levels |
| To regulate compressor pressure |
60
Stredne ťažká
What is the function of the temperature regulator in a refrigeration system?
| It restricts oil flow |
| It drains excess refrigerant into the receiver |
| Controls the operation of the compressor and valves to maintain the set temperature |
| To maintain a constant pressure in the compressor |
61
Stredne ťažká
What is the purpose of oil level regulators in a refrigeration system?
| They control the evaporator temperature |
| They control the pressure in the condenser |
| Maintains the correct oil level in the compressor |
| They drain off excess refrigerant |
62
Stredne ťažká
What is the function of the refrigerant receiver in the system?
| Stores excess refrigerant and facilitates the detection of leaks |
| Regulates the oil flow |
| It controls the evaporator temperature |
| It maintains a constant pressure in the system |
63
Stredne ťažká
What is the role of the manifold thermometer in the refrigeration system?
| Controls the oil level |
| Relieves pressure in the system in the event of excessive pressure |
| It monitors the moisture content of the refrigerant |
| Measures the refrigerant temperature at the compressor inlet and outlet, which helps to identify leaks |
64
Stredne ťažká
What is the role of the defrost control valves?
| They drain off excess oil |
| They control the pressure in the compressor |
| They are used to monitor the moisture content of the refrigerant |
| Protect the evaporator from excessive icing and reduce the risk of leaks |
65
Stredne ťažká
Where can I find lists detailing fluorinated greenhouse gases (F-gases)?
| In the Act on Ozone-Depleting Substances and Certain Fluorinated Greenhouse Gases. |
| In the Vienna Convention for the Protection of the Ozone Layer. |
| In Regulation (EU) No 2024/573 of the European Parliament and of the Council |
| In the Regulation of the Minister for the Economy on the introduction of a list of fluorinated greenhouse gases. |
66
Stredne ťažká
Where can I find the lists specifying controlled substances?
| In the Regulation of the Minister for the Environment on the list of controlled substances. |
| In Regulation (EU) No 2024/590 of the European Parliament and of the Council. |
| In the current Act on Ozone-Depleting Substances and Certain Fluorinated Greenhouse Gases. |
| In the Vienna Convention for the Protection of the Ozone Layer. |
67
Stredne ťažká
Where and by when should annual reports on ODS and F-gases be submitted?
| Reports on ODS and F-gases for the previous year must be submitted by 28 February of the following year, via the IT system available in the reports database at the Office for the Protection of the Ozone Layer and Climate (BOWOiK) on the ICHP website. |
| Reports must be submitted by the end of the relevant calendar year, using a special form at the regional branch of the Office of Technical Inspection (UDT) |
| Reports for the previous year must be submitted by 31 March of the relevant year electronically to the Ministry of the Environment. |
| Reports for the previous year must be submitted by 31 January electronically by completing the special forms available in the central register of operators ‘CRO’. |
68
Stredne ťažká
Which measure has the greatest impact on improving the compressor’s energy efficiency during installation?
| Installation without filters |
| Correctly create a vacuum and remove moisture from the system |
| Installation without a leak test |
| Increasing the amount of refrigerant |
69
Stredne ťažká
How does regular monitoring of the oil level affect the compressor’s operation?
| Ensures proper lubrication and improves energy efficiency |
| It reduces cooling capacity |
| It has no effect |
| Causes a rise in pressure |
70
Stredne ťažká
How do system leaks affect the compressor’s energy efficiency?
| Have no effect |
| They lower the operating temperature |
| These cause a drop in performance and an increase in energy consumption |
| They improve efficiency |
71
Stredne ťažká
Regulation (EC) No 2024/590 relates to:
| Alternative refrigerants serving as substitutes for fluorinated greenhouse gases. |
| Ozone-depleting substances. |
| Health and safety at work during the recovery of refrigerants. |
| The conditions for obtaining F-gas certificates by companies carrying out the recovery and reclamation of waste refrigerants. |
72
Stredne ťažká
What is the significance of regulating suction and discharge pressure?
| Helps maintain optimal operating conditions for the compressor |
| Increases oil consumption |
| Causes leaks |
| It has no effect on efficiency |
73
Stredne ťažká
What maintenance measure reduces the compressor’s energy consumption?
| Disabling safety devices |
| Regular replacement of filters and dryers |
| Lack of servicing |
| Increasing the refrigerant charge |
74
Stredne ťažká
How does the presence of air in the refrigeration system affect performance?
| Leads to increased pressure and reduced efficiency |
| It improves efficiency |
| It has no effect |
| Reduces energy consumption |
75
Stredne ťažká
What role do control systems (e.g. regulators) play in compressor efficiency?
| It doesn’t matter |
| Causes leaks |
| It increases the amount of refrigerant |
| Enables optimisation of operation and a reduction in energy consumption |
76
Stredne ťažká
How does refrigerant superheat at the compressor suction affect performance?
| It always improves performance |
| It has no effect |
| Excessive overheating reduces efficiency and increases energy consumption |
| It only causes a drop in temperature |
77
Stredne ťažká
How does the correct layout of the system affect efficiency?
| It causes the temperature to rise |
| It doesn’t matter |
| Shortens flow paths and reduces energy losses |
| It increases the pressure |
78
Stredne ťažká
How important is pipe insulation?
| Reduces heat loss and improves energy efficiency |
| It has no effect |
| Causes a rise in pressure |
| It increases energy consumption |
79
Stredne ťažká
Which measure most improves the condenser’s energy efficiency?
| Restricted airflow |
| Regular cleaning of heat exchange surfaces |
| Increasing the amount of refrigerant |
| Contamination of the heat exchange surface |
80
Stredne ťažká
How does a dirty condenser affect the operation of the refrigeration system?
| It has no effect |
| It improves efficiency |
| It lowers the condensing pressure |
| Causes an increase in pressure and energy consumption by the compressor |
81
Stredne ťažká
Why is adequate airflow through an air-cooled condenser important?
| Ensures effective heat dissipation and improves energy efficiency |
| Insufficient airflow reduces efficiency |
| Causes a drop in pressure |
| It doesn’t matter |
82
Stredne ťažká
Which refrigerants cause damage to the ozone layer?
| All refrigerants that contain chlorine or bromine in their molecules. |
| All refrigerants that are hydrocarbon derivatives. |
| All refrigerants that contain carbon in their molecular structure. |
| All refrigerants that contain fluorine and hydrogen in their molecules. |
83
Stredne ťažká
How does the presence of limescale in a water-cooled condenser affect performance?
| It improves heat transfer |
| Impairs heat exchange and increases energy consumption |
| It lowers the condensation temperature |
| It has no effect |
84
Stredne ťažká
How does correct condensation pressure control affect efficiency?
| It increases energy consumption |
| Maintains optimum operating conditions and reduces energy consumption |
| Causes leaks |
| It has no effect |
85
Stredne ťažká
How do condenser leaks affect energy efficiency?
| Causes refrigerant loss and a drop in efficiency |
| They improve efficiency |
| Have no effect |
| They lower the temperature |
86
Stredne ťažká
How important is the correct positioning of an air-cooled condenser?
| It should be housed in a small room |
| It should be close to heat sources |
| It should be installed in a well-ventilated area with unobstructed airflow |
| It doesn’t matter |
87
Stredne ťažká
How does hot air recirculation affect the condenser?
| Impairs cooling and increases energy consumption |
| It has no effect |
| It reduces the pressure |
| It improves efficiency |
88
Stredne ťažká
How does the insulation of central heating and domestic hot water pipework affect the operation of the heat pump’s condenser?
| It doesn’t matter |
| It impairs cooling |
| It increases the pressure |
| Reduces energy losses and improves the efficiency of the entire system |
89
Stredne ťažká
Which measure most improves the energy efficiency of the evaporator?
| Restricted airflow |
| Regular defrosting of the evaporator |
| Increasing the condensation temperature |
| Increasing the amount of refrigerant |
90
Stredne ťažká
How does evaporator icing affect the system’s operation?
| It has no effect |
| It improves cooling performance |
| It lowers the condensation temperature |
| Impairs heat exchange and increases energy consumption |
91
Stredne ťažká
How does dirt on the evaporator surface affect its performance?
| It reduces the pressure |
| It improves efficiency |
| It has no effect |
| Impairs heat exchange and increases energy consumption |
92
Stredne ťažká
What maintenance task is crucial for the evaporator?
| Lack of maintenance |
| Reduced airflow |
| Regular cleaning and defrosting |
| Increasing the refrigerant charge |
93
Stredne ťažká
What does an F-gas personal certificate (Category A2) authorise?
| to make permanent joints by brazing in systems containing fluorinated greenhouse gases. |
| to repair, maintain or service refrigeration equipment and systems containing controlled substances. |
| To recover refrigerant from equipment containing less than 3 kg of fluorinated greenhouse gases, or less than 6 kg in the case of hermetically sealed systems. |
| for the purchase of lubricants and refrigeration oils, and for the testing of safety valves. |
94
Stredne ťažká
How does superheating of the refrigerant at the evaporator outlet affect efficiency?
| It has no effect |
| Excessive superheat reduces energy efficiency |
| It always improves performance |
| It only causes a drop in temperature |
95
Stredne ťažká
How do leaks in the evaporator affect efficiency?
| Improves performance |
| These cause refrigerant loss and a drop in efficiency |
| Increase capacity |
| Have no effect |
96
Stredne ťažká
How important is correct expansion valve adjustment?
| Ensures optimal evaporator charge and improves efficiency |
| Causes leaks |
| It doesn’t matter |
| It increases energy consumption |
97
Stredne ťažká
How does inadequate insulation of the heat transfer circuit pipes affect evaporator performance?
| It lowers the condensation temperature |
| It has no effect |
| Causes cooling losses and increased energy consumption |
| It improves efficiency |
98
Stredne ťažká
How does correct TEV valve adjustment affect the system’s energy efficiency?
| It increases energy consumption |
| Causes leaks |
| Ensures optimum superheat and improves system efficiency |
| It has no effect |
99
Stredne ťažká
What happens if the superheat set by the TEV is too high?
| Cooling efficiency will improve |
| The refrigerant charge will increase |
| It has no effect |
| Efficiency will drop because the evaporator is not being fully utilised |
100
Stredne ťažká
How does a low superheat setting on the TEV affect performance?
| It has no effect |
| It reduces refrigerant flow |
| It may lead to improved efficiency, but it increases the risk of the compressor becoming flooded with liquid |
| It increases operational safety |
101
Stredne ťažká
How do contaminants in the system affect the operation of the TEV?
| They improve its performance |
| They can cause it to become blocked and reduce efficiency |
| Have no effect |
| They lower the temperature |
102
Stredne ťažká
What role does the filter-drier play in terms of system efficiency?
| It increases the amount of refrigerant |
| It doesn’t matter |
| Removes moisture and contaminants, improving the system’s efficiency |
| It lowers the temperature |
103
Stredne ťažká
How does proper insulation of components (e.g. pipes near the TEV) affect the system?
| Prevents unwanted heat gains and improves efficiency |
| It increases energy consumption |
| It causes leaks |
| It doesn’t matter |
104
Stredne ťažká
What does Regulation (EU) No 2024/573 of the European Parliament and of the Council cover?
| The Regulation sets out health and safety requirements for soldering work. |
| The Regulation concerns gases that contribute to the greenhouse effect. |
| The Regulation concerns leak testing of stationary refrigeration, air-conditioning and heat pump equipment containing fluorinated greenhouse gases. The Regulation sets out the requirements relating to leak testing of such equipment. |
| The Regulation sets out requirements relating to brazing of refrigeration systems. |
105
Stredne ťažká
How important is it to check the operation of the condensing pressure control valve in the system?
| It has no effect |
| Ensures operation within the optimum pressure range and reduces energy losses |
| It increases energy consumption |
| It causes a significant rise in temperature |
106
Stredne ťažká
How does the correct selection of a TEV affect energy efficiency?
| It increases the amount of refrigerant |
| Ensures the system is matched to its capacity and operates optimally |
| It doesn’t matter |
| It lowers the temperature |
107
Stredne ťažká
What is the main design difference in hydrocarbon-based refrigeration systems?
| Higher operating pressures |
| Lower energy efficiency |
| The need for explosion-proof measures due to the flammability of the refrigerant |
| No need for safety measures |
108
Stredne ťažká
What differences are there in the compressors used in hydrocarbon systems?
| They must operate at higher pressures |
| They must be designed to operate with flammable refrigerants (e.g. hermetic compressors) |
| No differences |
| They do not require lubrication |
109
Stredne ťažká
How can one check whether the system has been overcharged with refrigerant?
| This cannot be checked with sufficient reliability, as the sight glass is not designed for this purpose. |
| Under normal conditions, there is a marked increase in condensing pressure because an excessive amount of refrigerant accumulates in the condenser, reducing the heat exchange surface area within it. |
| The refrigeration system is overcharged with refrigerant whilst in operation, and even under a very small heat load, frost forms on the suction side of the compressor |
| The compressor will operate under a lower load and the suction pressure will decrease |
110
Stredne ťažká
Before charging the refrigeration unit with refrigerant, it is essential to…
| carry out a start-up test. |
| carry out a leak test. |
| complete the unit’s data sheet. |
| check the compressor’s suction and discharge connections. |
111
Stredne ťažká
What information must appear on the unit’s label?
| The manufacturer’s logo and the weight of the unit. |
| Among other things: information stating that the unit contains a fluorinated greenhouse gas, together with the industrial designation of the gas or its chemical name, the mass of the gas and its CO₂ equivalent |
| It does not matter what should be included on the device label. |
| Markings regarding the weight and capacity of the pipework, together with the colour code and chemical composition of the paints used to coat the frame and casing. |
112
Stredne ťažká
What is the base unit of temperature according to the International System of Units (Système International d’Unités)?
| °R |
| K |
| °F |
| °C |
113
Stredne ťažká
Which of the following are the most important pieces of information that should be included in the unit’s data sheet:
| Information regarding refrigerant recovery and unit dismantling. |
| The owner, installer and service technician of the unit. |
| Operator details, unit details, type and quantity of refrigerant, information regarding servicing and repairs. |
| The make and model of the unit, so that the manufacturer can be contacted to obtain the technical information necessary for servicing. |
114
Stredne ťažká
Who is responsible for drawing up the equipment or installation record?
| The person responsible for risk assessment. |
| The operator of the unit or system. |
| There is no such obligation. |
| The equipment maintenance technician. |
115
Stredne ťažká
Oil traps on the suction pipework are required:
| at the inlet to each component of the refrigeration system. |
| always before any rise in the pipeline. |
| before the compressor. |
| before the safety valve. |
116
Stredne ťažká
When is there a refrigerant leak, even though the compressor is still running?
| When we observe a rise in the refrigerant level in the liquid receiver and the subcooling increases. |
| When the suction pressure is low, superheat is high, subcooling is negligible and the temperature difference between the condenser and the expansion valve is small. |
| When the sight glass is full of liquid refrigerant and we observe a rise in the oil level in the compressor sump. |
| When the condensing pressure and suction pressure rise, but there is no superheat. |
117
Stredne ťažká
Which components of a refrigeration system can be classified as potential leak points (leaks) subject to regular leak tests?
| Fittings, valves including their stems, seals – including those in replaceable filters and dryers, components exposed to vibration, and connections to measuring, control and safety devices. |
| All parts of the refrigeration unit that are connected to the suction side of the refrigeration system. |
| Hermetic compressors, liquid refrigerant tanks and liquid separators. |
| Parts of the system located on the high-pressure side (from the compressor up to and including the expansion valve). |
118
Stredne ťažká
What is the test pressure during the pressure leak test of the unit?
| According to the PN-EN 378 standard, at least 0.25 times the maximum permissible pressure for the system (PS). |
| The test pressure (maximum) is 30 bar. |
| The test pressure for leak testing is equivalent to the maximum operating pressure measured during the operation of the refrigeration unit. |
| The test pressure is determined by the person carrying out the leak test based on their experience. |
119
Stredne ťažká
In which part of the refrigeration unit must the recommended leak test be carried out?
| The check should only be carried out at the connection points for measuring instruments (pressure switches, pressure gauges, temperature sensors). |
| The test must be carried out at all points on the refrigeration unit where there is a potential risk of refrigerant leakage. |
| The test must be carried out on the compressor shut-off valves, solenoid valves and filters. |
| The check must be carried out on all parts of the refrigeration system that are connected to the discharge side of the refrigeration circuit. |
120
Stredne ťažká
When can a given unit be considered perfectly leak-tight?
| A device can be considered perfectly leak-tight if gas bubbles appear when it is submerged in water. |
| The device in question is perfectly leak-tight when we have carried out a check using a permanently installed electronic detector. |
| A given unit can be considered perfectly leak-tight if, during a leak test, the pressure remains constant, taking into account pressure changes caused by temperature variations. Any drop in pressure indicates a leak and requires the location of the leak to be identified. |
| A given device can be considered perfectly leak-tight when the pressure drop during the test does not exceed 0.1 bar. |
121
Stredne ťažká
What does EU Regulation 1516/2007 cover?
| The Regulation sets out health and safety requirements for soldering work. |
| The Regulation addresses the disposal of gases that contribute to the greenhouse effect. |
| The Regulation concerns leak testing of stationary refrigeration, air-conditioning and heat pump equipment containing fluorinated greenhouse gases. The Regulation sets out the requirements for leak testing of such equipment. |
| The Regulation sets out requirements relating to brazing of refrigeration systems. |
122
Stredne ťažká
How should the pressure be increased during a pressure leak test?
| We increase the pressure gradually whilst checking for leaks, until the test pressure is reached, at a rate of no more than 2 bar/min |
| We increase the pressure as quickly as possible. |
| We increase the pressure in any way. |
| We increase the pressure at a rate of 10 bar/s. |
123
Stredne ťažká
What electronic equipment should be used to carry out leak testing?
| Only with devices fitted with an infrared detector. |
| Only with devices fitted with an ‘Ion Pump’ sensor. |
| Only using devices with verified measurement sensitivity. |
| Only with devices fitted with hot cathodes. |
124
Stredne ťažká
What documentation should be checked before starting a leak test?
| The maintenance log and the machine/device operating instructions must be checked. |
| Check the operating instructions for the machine/equipment. |
| Check the stock ledger (accounts). |
| Check the time sheets of the staff responsible for the machinery/equipment. |
125
Stredne ťažká
What information must be recorded when drawing up the leak test report?
| The date of the inspection, the number of faults (leaks), the location of the faults (leaks), the proposed method of rectifying the fault/defect (leak), attached documents and a signature. |
| The date of the inspection, a record of the occurrence of the leak, and a signature. |
| The number of locations where leaks have occurred and the date of the inspection. |
| The method used to carry out the leak test, the number of faults, the method of repairing the faults, the time taken to work on the installation, and the cost of the repair. |
126
Stredne ťažká
What pressure values should be used for the pressure leak test?
| At the discretion of the person authorised to carry out the pressure test. |
| Use a pressure not exceeding the maximum permissible pressure for the system (PS). |
| The pressure value for the leak test is 10–12 bar. |
| The pressure for the leak test is 2–3 bar. |
127
Stredne ťažká
What is temperature slip?
| A specific temperature cannot be assigned to a given vapour pressure. There is a temperature difference between the start and end of evaporation. |
| It involves a decrease in temperature. |
| It involves an increase in temperature. |
| A specific temperature corresponds to a given vapour pressure. |
128
Stredne ťažká
In which appliances and systems is the installation of a permanent leak detection system required?
| In equipment and systems containing at least 5 tonnes of CO₂ equivalent. |
| In equipment and systems containing at least 50 tonnes of CO₂ equivalent. |
| In equipment and installations containing at least 30 kg of fluorinated greenhouse gases. |
| In equipment and systems containing at least 500 tonnes of CO₂ equivalent. |
129
Stredne ťažká
Which category of F-gas certificate (A1, A2, B, C, D, E) authorises the performance of leak tests on refrigeration equipment:
| Categories D and E. |
| Category E only. |
| All except category D. |
| Only categories A1 and A2. |
130
Stredne ťažká
Why is it advisable to subcool the liquid refrigerant?
| This is advisable because it allows a smaller expansion valve to be used (less superheat at the valve). |
| This is advisable because it allows a smaller condenser to be used (smaller heat exchange surface area). |
| This is advisable because it ensures that the liquid refrigerant, free of vapour bubbles, enters the expansion valve. |
| This is advisable because it allows a smaller evaporator to be used (lower refrigerant temperature at the evaporator inlet). |
131
Stredne ťažká
What should be done following repairs to a leak in the refrigeration unit of a refrigerated trailer?
| A visual inspection should be carried out only on bolted and soldered joints. |
| You must enter the details into the equipment log (including the quantities of refrigerant recovered and used) and inform the Operator that an additional leak test must be carried out by a certified person within one month of the repair. |
| An invoice for the service work carried out must be issued as soon as possible. |
| The unit must be charged with an alternative refrigerant, started up, and the refrigerant parameters checked at the service valve located on the liquid receiver. |
132
Stredne ťažká
Recovery of fluorinated greenhouse gases means:
| The reuse of fluorinated greenhouse gases following a basic purification process. |
| The collection and storage of fluorinated greenhouse gases originating, for example, from machinery, equipment and containers. |
| The final decommissioning and withdrawal from service or use of a product or piece of equipment containing fluorinated greenhouse gases. |
| The reprocessing of fluorinated greenhouse gases to achieve their specified standard properties. |
133
Stredne ťažká
Who is authorised to recover refrigerant from stationary refrigeration equipment:
| A service technician holding an F-gas certificate in the relevant category. |
| The operator. |
| The owner of the installation. |
| The administrator of the operator’s account. |
134
Stredne ťažká
Recovered refrigerants must be stored:
| In any pressure vessel that has been officially certified. |
| In a specially adapted and labelled cylinder fitted with a two-way valve. |
| In any used refrigerant cylinder. |
| In a cylinder that previously contained the same type of refrigerant. |
135
Stredne ťažká
When should the recovery of fluorinated greenhouse gases be carried out:
| Always during servicing and maintenance of equipment. |
| Before the final disposal of equipment and, where applicable, during its servicing and maintenance. |
| Only prior to the final disposal of equipment. |
| Before each leak test of the equipment. |
136
Stredne ťažká
What should be done if the refrigerant recovered from the system is contaminated, e.g. with acid, air or moisture?
| Add a special contaminant neutraliser to the mixture. |
| You should attempt to purify the mixture yourself using a dehydrating filter. |
| Purify the mixture by passing it through a particulate filter and reuse it. |
| Such a mixture must be handed over to a specialist authorised company for regeneration or disposal. |
137
Stredne ťažká
What should be done if different types of refrigerants become mixed in a storage cylinder (container)?
| The mixture should be purified by passing it through a filter-drain and reused. |
| Add a special refrigerant to the mixture. |
| Send this mixture to a specialist authorised company to have it neutralised. |
| You should attempt to separate the mixture into its individual components. |
138
Stredne ťažká
How does refrigerant recovery using the Push-Pull method work?
| This involves using a suction device (compressor) to ensure that the refrigerant, in liquid form, is transferred into the cylinder. |
| This involves the refrigerant being alternately drawn from the suction side and then from the discharge side of the refrigeration unit (compressor). |
| This involves injecting nitrogen from the cylinder into the unit and expelling the liquid refrigerant from the unit. |
| It involves using a recovery unit to draw (pull) the refrigerant vapour from the cylinder and then force it (push) into the low-pressure side of the system. |
139
Stredne ťažká
What are the methods for managing waste refrigerant?
| Recycling, regeneration, disposal. |
| Regeneration, recovery. |
| Disposal, storage. |
| Recovery, disposal. |
140
Stredne ťažká
The most advantageous method of managing waste refrigerant is:
| Disposal. |
| Regeneration. |
| Storage. |
| Recycling. |
141
Stredne ťažká
The lower the evaporation temperature, ...
| ...the lower the density of the refrigerant and the lower the mass of the flowing refrigerant. |
| ...the greater the density of the refrigerant and the mass flow rate of the flowing refrigerant. |
| ...the lower the refrigerant density, and the greater the cooling capacity of the compressor. |
| …the greater the density of the refrigerant and the lower the mass flow rate of the refrigerant. |
142
Stredne ťažká
How should pressure vessels (e.g. refrigerant cylinders) be marked?
| They should bear the manufacturer’s logo and the date of manufacture. |
| It is irrelevant how pressure vessels should be marked. |
| They should bear only markings relating to weight and capacity. |
| They should bear, amongst other things, information such as: the number of the standard applied to their design, construction and testing; the identification marks of the country of approval and the inspection body; the date of the acceptance test; and the manufacturer’s and operational marks. |
143
Stredne ťažká
The recovery of refrigerants does not require the use of:
| A refrigerant recovery station. |
| Hoses with shut-off valves. |
| An electronic leak detector. |
| Scales with a measurement range suitable for the size of the cylinder being filled. |
144
Stredne ťažká
What functions does the compressor perform in a refrigeration system?
| The compressor condenses the refrigerant. |
| The compressor draws in refrigerant vapour from the evaporator, compresses it, and then forces it into the condenser, raising the pressure to the required condensing pressure. |
| The compressor compresses ambient air and increases the pressure of the refrigerant. |
| The compressor creates a vacuum on the suction side of the system |
145
Stredne ťažká
What is compressor flooding?
| Flooding the compression chamber with liquid refrigerant or oil. |
| A large amount of liquid refrigerant in the evaporator. |
| Flooding of the compressor due to rainfall. |
| Suction of liquid refrigerant into the compressor’s suction line. |
146
Stredne ťažká
To what extent do we regulate the compressor motor’s rotational speed when using a frequency converter?
| Up to a maximum of 10 per cent. |
| Approximately from 30 to 75 Hz, which corresponds to around 60% to 150% of the cooling capacity. |
| From approximately 30% to 90% of capacity. |
| Regulating the compressor motor speed is not the same as regulating the cooling capacity. |
147
Stredne ťažká
Why is it essential to observe the correct phase sequence for scroll compressors and screw compressors?
| Because the motor speed would decrease, and consequently the compressor’s capacity. |
| Because these types of compressors are sensitive to voltage drops. |
| Because this type of compressor has difficulty starting up if the phase sequence is changed. |
| Because changing the phase sequence would reverse the direction of rotation of the compressor rotors, which could result in damage to the compressors. |
148
Stredne ťažká
The cycle of a two-stage vapour-compression refrigeration system should have, in each stage of the system:
| a compression ratio greater than 8. |
| a compression ratio of less than 6 |
| a compression ratio of less than 18. |
| a compression ratio of less than 8. |
149
Stredne ťažká
Why is it necessary to seal the shafts in gland-sealed refrigeration compressors?
| Because it protects the compressor’s crankshaft bearing. |
| Because it prevents oil leakage. |
| Because we need to prevent air from entering the compressor and we need to prevent refrigerant from leaking from the compressor. |
| Because it ensures the bearing remains lubricated. |
150
Stredne ťažká
When is the refrigerant sufficiently cooled?
| When the liquid distributors are warm. |
| When the evaporator is covered in frost. |
| When no vapour bubbles are observed forming in the liquid sight glass. |
| When the outlet from the condenser is cold. |
151
Stredne ťažká
Why should the compressor crankcase be heated?
| Heating ensures that the lubricating oil is de-watered. |
| Heating keeps the lubricating oil in a liquid state. |
| Heating improves the dissolution of the refrigerant in the oil, which is beneficial for its viscosity. |
| Heating prevents the refrigerant from dissolving in the oil. |
152
Stredne ťažká
What are compressor sets?
| These are sets comprising several compressors connected in any configuration. |
| These are multiple (several) air-cooled condensers. |
| These consist of a larger number (several) of compressors connected in parallel and mounted on a common frame. |
| These are units consisting of two-stage compressors. |
153
Stredne ťažká
What are the advantages of compressor units?
| Easy modification of the system. |
| These are inexpensive and easy-to-install units. |
| Space-saving and lower energy consumption. |
| The ability to adjust the cooling capacity as required. |
154
Stredne ťažká
What do we mean by the ‘application range’ of a compressor?
| By this term, we mean that the compressor’s operating range is determined by the evaporation temperature ‘to’ during operation. |
| By this term, we mean the following parameters: the evaporation and condensation temperatures (to and tk), or the pressure values that determine the compressor’s application. |
| By this term, we mean the following parameters: compressor capacity, type of refrigerant, and the compressor’s geometric dimensions. |
| By this term, we mean that the compressor’s application range is determined by the evaporation temperature ‘to’ at a given ambient temperature. |
155
Stredne ťažká
What are the basic functions of oil in a compressor?
| The oil seals the gap between the piston and the cylinder. |
| The oil seals any leaks that develop in the system. |
| The oil lubricates both the bearings and the sliding surfaces of the compressor components, and cools the compressor by transferring the heat generated during compression to the compressor’s outer casing. |
| The oil absorbs moisture from the refrigerant that enters the compressor. |
156
Stredne ťažká
What are the most effective ways of regulating the compressor’s cooling capacity?
| By means of pressure control valves. |
| Using an expansion valve. |
| By partially covering the evaporator to reduce the heat exchange surface area. |
| By changing the compressor’s displacement, by varying the rotational speed, or by deactivating individual cylinders. |
157
Stredne ťažká
What does compressor bypass control involve?
| Refrigerant in the form of cooled, high-pressure vapour is introduced into the suction line. |
| The bypass control is not used to regulate the compressor. |
| Hot, high-pressure refrigerant vapour is drawn in on the suction side of the compressor. |
| High-pressure liquid refrigerant is injected on the suction side of the compressor. |
158
Stredne ťažká
What is the fundamental difference between hermetic and semi-hermetic compressors?
| The housing of a hermetic compressor and the compressor itself form a single unit. |
| The casing of semi-hermetic compressors can be dismantled, whereas the casing of hermetic compressors cannot be dismantled. |
| Semi-hermetic compressors are characterised by the quiet operation of the entire unit. |
| Both types of compressors are disassemblable, and the difference lies in their varying capacities. |
159
Stredne ťažká
How does a scroll compressor work?
| It is a device fitted with two spirals. It is a type of positive displacement (volumetric) compressor in which compression takes place through the interaction of the two spirals. |
| It is a type of piston-type device. |
| It uses two screws to compress the refrigerant. |
| A scroll compressor is also known as a turbo compressor. |
160
Stredne ťažká
What physical process takes place in the evaporator?
| It causes the refrigerant flowing through it to condense. |
| The liquid refrigerant evaporates and a small amount of it becomes superheated. |
| It cools the refrigerant flowing through it. |
| The medium flowing through the evaporator (glycol, water) evaporates, whilst the refrigerant condenses. |
161
Stredne ťažká
What is the purpose of regulating the compressor’s capacity?
| Capacity control protects the compressor from low thermal loads. |
| It ensures that the cooling capacity is adjusted based on condensing temperatures. |
| It allows the cooling capacity to be adjusted to meet requirements. |
| It ensures adequate lubrication of the compressor. |
162
Stredne ťažká
Why is inverter speed control suitable for refrigeration compressors?
| By reducing the speed of the refrigeration compressor motor, inverter speed control improves the return oil flow to the compressor. |
| Inverter speed control can be used with any type of compressor to ensure adequate lubrication. |
| Inverter speed control enables continuous, smooth regulation of cooling capacity. |
| Inverter speed control reduces energy consumption only under natural conditions. |
163
Stredne ťažká
Does the suction gas temperature affect the cooling capacity of the compressor?
| Temperature has no effect on the compressor’s cooling capacity. |
| It has a significant effect on performance. |
| It does, but only for reciprocating compressors. |
| It does, but only if the gas is deeply cooled. |
164
Stredne ťažká
In the case of compressor units fitted with an oil level control system, is it necessary to install the compressors at the same height?
| Only screw compressors. |
| No. |
| Yes. |
| Only scroll compressors. |
165
Stredne ťažká
What functions does a compressor powered by the vehicle’s engine perform in a transport refrigeration system?
| The compressor compresses ambient air and increases the pressure of the refrigerant. |
| This compressor draws in refrigerant vapour from the evaporator, compresses it and then forces it into the condenser whilst the vehicle’s engine is running. |
| This compressor creates a vacuum on the suction side of the system whilst the vehicle’s engine is switched off. |
| This compressor condenses the refrigerant whilst the vehicle is in motion. |
166
Stredne ťažká
Which natural fluids absorb heat from the refrigerant in the condenser?
| Water and an antifreeze mixture. |
| Air and CO2. |
| Water or air. |
| Ammonia |
167
Stredne ťažká
What is the function of the condenser in refrigeration systems?
| Heat released in the regenerative heat exchanger is absorbed by the condenser. |
| Heat from the compressor is then released into the environment via the condenser. |
| The heat absorbed in the evaporator is then released into the environment via the condenser |
| The heat absorbed in the evaporator and transferred during the compression process is then released into the environment via the condenser. |
168
Stredne ťažká
If the condensation temperature is higher than the critical point temperature of the refrigerant, condensation:
| temperature has no effect on condensation. |
| will always occur regardless of the temperature. |
| will not occur. |
| will occur provided a specially designed condenser is used. |
169
Stredne ťažká
How does the subcooling of the refrigerant take place within a refrigeration system?
| Subcooling of the refrigerant using oil (dissolving the refrigerant in oil). |
| Subcooling using high-pressure hot vapour. |
| Subcooling of the liquid refrigerant in the final section of the condenser. |
| Subcooling using an additional heat exchanger and liquid nitrogen. |
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Stredne ťažká
What is the purpose of controlling the condenser fan speed?
| Condenser fan speed control reduces energy efficiency. |
| Dispersion of the refrigerant in the event of a system leak. |
| Condenser fan speed control ensures that the condensing pressure is maintained at the correct level. |
| Condenser fan speed control safeguards against the maximum permissible condensing pressure. |



