摘要 |
<p>There is provided a heat pump system comprising two cascade coupled heat pumps. The hot side of the system may be connected in series with an oil-fired boiler in a radiator circuit of conventional water heating installation, wherein a hot water heater is coupled in parallel to the boiler. The low temperature heat pump has two series connected condensors of which one is connected to the evaporator of the high temperature heat pump, while the other is useful for heating radiator water flowing in a shunt pipe parallel with the boiler. A threeway shunt valve controls the mix of water of different temperatures from the boiler and the shunt pipe respectively, so that water of a desired temperature is let into the raiser pipe of the radiator circuit.</p> |