F-Gas English Low GWP
Všetky otázky
HFC | Flammable | CO₂ | NH₃
Ľahké otázky |
Stredne ťažké otázky |
Ťažké otázky
1
Ľahká
What is the base unit of mass in the International System of Units (SI)?
| N |
| t |
| lb (pound) |
| kg |
2
Ľahká
The refrigerant absorbs heat when…
| …it condenses |
| …it freezes |
| …it is subcooled |
| …it evaporates |
3
Ľahká
What does the GWP indicator mean?
| Global Warming Potential: the climate warming impact of 1 kg of a gas compared with 1 kg of CO₂ (GWP = 1) over a defined time horizon, usually 100 years |
| Ozone depletion potential |
| The ability of a substance to restore the ozone layer |
| The annual rise in mean air temperature caused by the emission of 1 kg of the gas |
4
Ľahká
What is the main function of a safety valve?
| It monitors the moisture content of the refrigerant |
| Prevents the evaporator from freezing |
| Discharges refrigerant when the set pressure is exceeded |
| It controls the oil level in the compressor |
5
Ľahká
What is the unit of pressure in the International System of Units (SI)?
| atm (standard atmosphere) |
| Pa (pascal) |
| bar (gauge) |
| psi (pound per square inch) |
6
Ľahká
How do system leaks affect compressor energy efficiency?
| They improve efficiency because condensing pressure drops |
| Refrigerant loss reduces capacity and increases energy use (longer run times, higher superheat) |
| They affect only safety, not energy use |
| No effect as long as the system still cools |
7
Ľahká
How does a dirty condenser affect the operation of the refrigeration system?
| Causes an increase in pressure and energy consumption by the compressor |
| It lowers the condensing pressure |
| It improves efficiency |
| It has no effect |
8
Ľahká
Why is adequate airflow through an air-cooled condenser important?
| The lower the airflow, the lower the condensing pressure |
| It doesn't matter |
| It affects only noise |
| It ensures effective heat rejection and low condensing pressure |
9
Ľahká
How does the presence of limescale in a water-cooled condenser affect performance?
| It has no effect |
| It improves heat transfer |
| Impairs heat exchange and increases energy consumption |
| It lowers the condensation temperature |
10
Ľahká
How do condenser leaks affect energy efficiency?
| Causes refrigerant loss and a drop in efficiency |
| Have no effect |
| They improve efficiency |
| They lower the temperature |
11
Ľahká
How important is the correct positioning of an air-cooled condenser?
| It doesn’t matter |
| It should be close to heat sources |
| It should be installed in a well-ventilated area with unobstructed airflow |
| It should be housed in a small room |
12
Ľahká
How does hot air recirculation affect the condenser?
| It has no effect |
| It reduces the pressure |
| Impairs cooling and increases energy consumption |
| It improves efficiency |
13
Ľahká
How does evaporator icing affect the system’s operation?
| It has no effect |
| Impairs heat exchange and increases energy consumption |
| It improves cooling performance |
| It lowers the condensation temperature |
14
Ľahká
How does dirt on the evaporator surface affect its performance?
| Impairs heat exchange and increases energy consumption |
| It improves efficiency |
| It reduces the pressure |
| It has no effect |
15
Ľahká
What maintenance task is crucial for the evaporator?
| Reduced airflow |
| Lack of maintenance |
| Regular cleaning and defrosting |
| Increasing the refrigerant charge |
16
Ľahká
How does superheat at the evaporator outlet affect efficiency?
| It always improves performance |
| It only causes a temperature drop |
| Excessive superheat reduces energy efficiency |
| It has no effect |
17
Ľahká
How do leaks in the evaporator affect efficiency?
| Have no effect |
| Increase capacity |
| Improves performance |
| These cause refrigerant loss and a drop in efficiency |
18
Ľahká
How important is correct expansion valve adjustment?
| It increases energy consumption |
| Ensures optimal evaporator charge and improves efficiency |
| It doesn’t matter |
| Causes leaks |
19
Ľahká
How does inadequate insulation of suction (or secondary-coolant) pipes affect evaporator performance?
| It improves efficiency |
| It causes cooling losses and increased energy use |
| It lowers the condensing temperature |
| It has no effect |
20
Ľahká
How does correct TEV adjustment affect system energy efficiency?
| It increases energy use |
| It causes leaks |
| It ensures optimal superheat and improves efficiency |
| It has no effect |
21
Ľahká
What happens if the superheat set by the TEV is too high?
| Cooling efficiency will improve |
| It has no effect |
| Efficiency will drop because the evaporator is not being fully utilised |
| The refrigerant charge will increase |
22
Ľahká
How do contaminants in the system affect the operation of the TEV?
| They can cause it to become blocked and reduce efficiency |
| They lower the temperature |
| Have no effect |
| They improve its performance |
23
Ľahká
What role does the filter-drier play in terms of system efficiency?
| It lowers the temperature |
| Removes moisture and contaminants, improving the system’s efficiency |
| It doesn’t matter |
| It increases the amount of refrigerant |
24
Ľahká
How does proper insulation of components (e.g. pipes near the TEV) affect the system?
| It doesn’t matter |
| It causes leaks |
| It increases energy consumption |
| Prevents unwanted heat gains and improves efficiency |
25
Ľahká
How important is it to check the operation of the condensing pressure control valve in the system?
| It increases energy consumption |
| It causes a significant rise in temperature |
| It has no effect |
| Ensures operation within the optimum pressure range and reduces energy losses |
26
Ľahká
How does the correct selection of a TEV affect energy efficiency?
| Ensures the system is matched to its capacity and operates optimally |
| It lowers the temperature |
| It increases the amount of refrigerant |
| It doesn’t matter |
27
Ľahká
What is the base unit of temperature according to the International System of Units (Système International d’Unités)?
| °C |
| °R |
| K |
| °F |
28
Ľahká
What is the superheat of refrigerant vapour?
| The difference between the actual vapour temperature and the saturation temperature corresponding to its pressure (expressed in K) |
| The difference between the condensing temperature and the ambient temperature |
| The difference between the saturation temperature and the actual liquid temperature in the liquid line |
| The amount of heat required to evaporate a liquid |
29
Ľahká
What is the compression ratio of a compressor?
| The ratio of absolute discharge pressure to absolute suction pressure (pc/po) |
| The amount of refrigerant compressed per cycle relative to heat capacity |
| The ratio of suction pressure to discharge pressure (po/pc) |
| The ratio of discharge pressure to the effective capacity of the compressor (p/Vk) |
30
Ľahká
What is the theoretical displacement (swept volume flow) of a compressor?
| The volume of refrigerant flowing in one piston cycle under actual operating conditions |
| A value expressed by the coefficient of performance (COP) |
| The volume of a single cylinder in cm³ |
| The volume of vapour drawn in per unit of time, determined by the compressor's geometry and speed (stated by the manufacturer, e.g. in m³/h) |
31
Ľahká
What is the clearance (dead) volume of a reciprocating compressor?
| The space between the underside of the piston and the crankcase cover |
| The volume between the valve plate and the piston crown at top dead centre |
| The space between the side of the piston and the cylinder |
| The volume between the valve plate and the piston at bottom dead centre |