ENGINE-DRIVEN HOT WATER SUPPLY CIRCUIT, AND ENGINE-DRIVEN HOT WATER SUPPLY SYSTEM USING SAME

摘要

Provided is a configuration for combining discharge gas bypasses when water temperature does not reach a target high temperature by only controlling the speed of a compressor. An engine-driven hot water supply circuit (1) drives a compressor (21) by means of an engine (30), and is provided with: a refrigerant-water heat exchanger (23) that exchanges heat between a discharge refrigerant and supply water; a water-water heat exchanger (31) that exchanges heat between engine cooling water and supply water downstream from the refrigerant-water heat exchanger (23); and an evaporator (25) that evaporates the refrigerant by exchanging heat with air. The capacity of the evaporator is larger than the capacity of the refrigerant-water heat exchanger. If the temperature of the supply water at the water-water heat exchanger outlet is lower than a target temperature, the engine speed is increased, and if the temperature of the supply water is lower than the target temperature after the upper limit of the engine speed determined from the upper limit of the discharge pressure has been reached, the opening of a discharge gas valve (26), which bypasses a discharge channel and an intake channel of the compressor (21), is adjusted within a range in which the upper discharge pressure of the compressor (21) is not exceeded.