A method for constructing a water circulation device including a water circulation circuit that circulates water heat-exchanged with a refrigerant heated by a heat pump includes: installing a heater in the water circulation device in contact with the water; depositing scale from the water on the heater by heating the heater while circulating the water in the water circulation circuit; and removing the heater from the water circulation device after the depositing.

A water heater may operate according to different modes. The water heater may include a storage tank configured to store water, at least one sensor configured to sense a temperature of the water and a temperature related to an outside of the water heater, a first heater assembly (comprising a heating element) configured to heat the water, a first controller configured to control the first heater assembly, a second heater assembly (comprising a heat pump system) configured to heat the water, an inverter connected with the heat pump system, and a second controller configured to control the heat pump system by adjusting an output frequency of the inverter.

A heat pump may include a compressor configured to compress a refrigerant, a first temperature sensor configured to detect an outdoor temperature, a second temperature sensor provided in heating pipes connected to a heating device that performs indoor heating and configured to detect a temperature of fluid flowing through the heating pipes, an outdoor heat exchanger configured to perform heat exchange between outdoor air and a refrigerant, a third temperature sensor configured to detect a temperature of the outdoor heat exchanger, and a controller. The controller may be configured to: control power to a boiler and/or to the compressor based on sensing values of the first, second, and third temperature sensors, calculate an expected efficiency of the heat pump based on the sensing value of the first temperature sensor and an initial target temperature, and control power to the boiler based on the expected efficiency.

A heat pump may include a compressor configured to compress a refrigerant, a first temperature sensor configured to detect an outdoor temperature, a second temperature sensor provided in heating pipes connected to a heating device, and a controller. Based on a first sensing value of the first temperature sensor, the controller may be configured to control a compressor, control power to a boiler, and/or calculate an expected efficiency of the heat pump. Based on the expected efficiency and/or a second sensing value of a second temperature sensor, the controller may be configured to control power to the boiler.

A supply-water warming system includes a steam compression heat pump circuit, a heat recovery heat exchanger, a heat source fluid line in which heat source fluid flows in the heat recovery heat exchanger and the evaporator in this order, a water supply line in which supply water flows in the heat recovery heat exchanger and the condenser in this order, a refrigerant flow rate adjustment section controlled based on the superheat degree of gas refrigerant flowing into the compressor and configured to adjust a refrigerant flow rate, a supply water flow rate adjustment section controlled based on the tapping temperature of the supply water flowing out of the condenser and configured to adjust a supply water flow rate, and a control section configured to control the refrigerant flow rate adjustment section and the supply water flow rate adjustment section.

A heating system for heating a fluid received at an inlet, the system including a first heating device disposed in a first heated line branched from the inlet, wherein a first flow of the fluid through the first heated line is configured to be modulated by a first valve; a second heating device disposed in a second heated line branched from the inlet, wherein a second flow of the fluid through the second heated line is configured to be modulated by a second valve; and a bypass line and a third valve disposed in the bypass line, wherein a flow through the bypass line is configured to be modulated by the third valve, wherein the first and second heating devices and the first, second and third valve are configured to cooperate to heat the fluid at an outlet received from the first and second heated line and the bypass line.

Provided is an indoor unit for a heat pump use apparatus, the indoor unit being a part of the heat pump use apparatus including a refrigerant circuit configured to circulate refrigerant, a heat medium circuit configured to allow a heat medium to flow through the heat medium circuit, and a heat exchanger configured to exchange heat between the refrigerant and the heat medium. The indoor unit is connectable to an outdoor unit accommodating the refrigerant circuit and the heat exchanger. The indoor unit accommodates a part of the heat medium circuit. The indoor unit includes a pressure protection device connected to the heat medium circuit, and an on-off device provided to be interposed between the heat medium circuit and the pressure protection device.

A system, an arrangement and method for heating and cooling of several building spaces-or buildings includes two or more building spaces or buildings, and a secondary thermal network including a supply line and a return line. The arrangement further comprises two or more building connections arranged parallel to each other and between the supply line and provided in connection with the two or more building spaces or buildings, a ground hole and a geothermal heat exchanger provided to the ground hole and arranged in connection with the secondary thermal network.

An apparatus for heating water has a tank for storing water and an air conditioning system that defines a refrigerant flow path through which refrigerant flows. The refrigerant flow path passes through the heat exchanger so that refrigerant heat is contributed to the tank. A control system controls operation of the water heating apparatus.

A thermodynamic boiler for delivering heat into at least one heating circuit, includes a compressor forming the compression function of a heat pump type loop using a compressible fluid of type R744, and includes a fuel burner which delivers heat into the compressible fluid.