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(11) | EP 1 972 871 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Hot water system |
| (57) A hot water system includes: a compressor (1) with variable operation capacity; a
four-way valve (2) for switching the direction of the refrigerating cycle; a plate
heat exchanger (10) for exchanging heat between water and a refrigerant; an electronic
expansion valve (6) for controlling the flow rate of the refrigerant to reduce the
pressure; and a heat exchanger (9) for exchanging heat between air and the refrigerant,
which are connected in that order by a pipeline (3) to form a refrigerating cycle
for circulating the refrigerant, thereby heating water. The hot water system further
includes; pressure detection means (Pd) disposed between the outlet of the compressor
(1) and the two-way valve (2), for detecting the pressure of the refrigerant discharged
from the compressor (1), wherein the speed of operation of the compressor (1) is controlled
according to the difference between the condensing temperature calculated from the
pressure detected by the pressure detection means (Pd) and a target condensing temperature.
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