Heating system

Abstract

Abstract A system for utilization of waste heat streams, such as from a power plant, for the heating of buildings or for other uses of heat streams under 200° F. employing preferably a multi-stage heat pump selectively operable to raise the temperature of the building heating system (heated fluid) above the temperature of the waste heat stream (heating fluid). The multi-stage heat pump comprises separate stages each including an evaporator, condenser and compressor, and a heat exchanger. The heat pump may be connected either as a counter flow heat pump or a parallel flow heat pump. The control of the system is in at least two different modes dependent upon the demand (load). In the low load mode heat transfer to the building heating system occurs without operation of the heat pump. In this mode heat transfer occurs with the heat exchanger operating in combination with passive evaporator-condensor action with the compressor of the heat pump being by-passed to maintain the heated fluid outlet temperature at a preset value by controlling mass flow of the heating fluid as a function of sensed heated fluid outlet temperature. Once the load increases past a predetermined point the heat pump is activated and maintains the heating fluid outlet temperature constant. At short peak loads the total mass flow into the heat pump is limited thus relying upon the heat pump to extract more heat from the heating fluid to meet the peak loads. The control of the heating fluid stream is preferably accomplished with a single valve controlled as a function of the three variables; (1.) heated fluid outlet temperatures; (2.) heating fluid outlet temperature; and (3.) mass flow.

Inventors

• 👤 Robert W. Timmerman

Bibliographic Details