21. Heat pumps have a high Coefficient of ______ (COP). Performance
a) Energy (Energie)
b) Performance (Leistung)

22. The COP measures the system's ______. energy efficiency
a) energy efficiency (Energieeffizienz)
b) installation cost (Installationskosten)

23. Many heat pumps achieve COP values of ______ or higher. 3
a) 2 (zwei)
b) 3 (drei)

24. A COP of 3 means 1 unit of electricity produces ______ units of heat. 3
a) 3 (drei)
b) 5 (fünf)

25. Heat pumps can work down to ______ °C outdoor temperatures. -25
a) -15 (minus 15)
b) -25 (minus 25)

26. Ground-source systems are also known as ______ heat pumps. geothermal
a) geothermal (Geothermie-)
b) hydronic (Hydronik-)

27. Heat pumps can provide ______ for households. hot water
a) hot water (Warmwasser)
b) ventilation (Belüftung)

28. Modern heat pumps integrate well with ______ systems. smart home
a) smart home (Smart-Home-)
b) industrial (Industrielle)

29. They require ______ maintenance over their lifespan. minimal
a) frequent (häufige)
b) minimal (geringe)

30. Heat pumps are often used in ______ buildings. new and energy-efficient
a) old and renovated (alte und renovierte)
b) new and energy-efficient (neue und energieeffiziente)

31. Heat pumps use an evaporator, compressor, condenser, and ______. expansion valve
a) thermostat (Thermostat)
b) expansion valve (Expansionsventil)

32. The refrigerant absorbs heat and changes from ______. liquid to gas
a) solid to liquid (fest zu flüssig)
b) liquid to gas (flüssig zu gasförmig)

33. The compressor increases the refrigerant’s ______. pressure and temperature
a) volume and density (Volumen und Dichte)
b) pressure and temperature (Druck und Temperatur)

34. In the condenser, the refrigerant releases ______ to the indoor space. heat
a) heat (Wärme)
b) cold air (kalte Luft)

35. The cycle repeats to maintain ______ temperatures. desired
a) stable (stabile)
b) desired (gewünschte)

36. Air-source heat pumps are easier to ______ than ground-source systems. install
a) operate (bedienen)
b) install (installieren)

37. Ground-source heat pumps need ______ loops for heat exchange. underground
a) underground (unterirdische)
b) above-ground (oberirdische)

38. Closed-loop ground systems circulate ______ through buried pipes. antifreeze
a) antifreeze (Frostschutzmittel)
b) water (Wasser)

39. Open-loop systems use water directly from a ______. well or lake
a) stream or ocean (Bach oder Ozean)
b) well or lake (Brunnen oder See)

40. Hybrid systems combine heat pumps with traditional ______ for flexibility. boilers
a) boilers (Kessel)
b) air conditioners (Klimaanlagen)