In dairy processes, there are significant simultaneous heating and cooling demands. A novel type of transcritical CO2 heat pump system is proposed, and its features and benefits are introduced. Based on the technical characteristics, primary energy-savings, and operating cost aspects, the CO2 heat pump system is simulated and compared to current heating and cooling systems used in dairy plants....

In this study, a novel dual-nozzle ejector enhanced vapor-compression cycle (DEVC) for solar assisted airsource heat pump systems is proposed. In DEVC, the use of the dual-nozzle ejector for recovering the expansion losses is a very promising approach to improve the cycle performance. A mathematical model of the DEVC is developed to predict its performance under specified operating conditions. ...

Demand for space cooling in Canada has significantly increased in the past 20 years, and in conjunction with space heating loads in the winter are placing larger peak loads on the electrical grid. As a result, utilities must increase their generating and transmission capacity to meet the peak annual demand, with much of the capacity going unused for large portions of the year. Additionally, bas...

office building, or school, or replace your heating and cooling system, you may want to consider a geothermal heat pump (GHP) system. GHP systems are also known as GeoExchange, ground-source, or water-source heat pumps (as opposed to air-source heat pumps). Regardless of what you call them, energy-efficient geothermal heat pumps are available today for both residential and commercial building a...

This paper describes the design and performance analysis of a variable-capacity heat pump system developed for a small [1800ft (167 m)] prototype net ZEH with an average design cooling load of 1.25 tons (4.4 kW) in five selected US climates. The heat pump integrates space heating and cooling, water heating, ventilation, and humidity control (humidification and dehumidification) functions into a...

Heating, Ventilation and Air Conditioning (HVAC) systems are one of the biggest energy consumers around the world. With the efforts of moving to sustainable energy consumption, heat-pump based HVAC systems have gained popularity due to their high efficiency and due to the fact that they are powered by electricity rather than by gas or oil. One drawback of heat-pump systems is that their efficie...

Ground-source heat pump (GSHP) systems can achieve a higher coefficient of performance than conventional airsource heat pump (ASHP) systems because the ground, which functions as the heat source or sink, is at a higher temperature in winter and lower in summer than the air temperature (Kavanaugh 1992; Kavanaugh et al 1997). In addition, there will likely be some mitigation against the effects o...

In this paper, a thermoelectric-assisted vapor compression cycle (TVCC) is proposed for applications in air-source heat pump systems. Compared with the basic vapor compression cycle (BVCC), the TVCC using a thermoelectric heat exchanger (THEX) could enhance the heating capacity of the system in an energy-efficient way. To demonstrate the performance characteristics of TVCC, a case study on this...

Air source heat pumps are widely used for residential heating because of their relatively low installation costs. Major disadvantages are that the heat output and COP decrease and the discharge temperature of the compressor increases as the outdoor temperature decreases. All of these factors usually lead to the need of combined heat pump and backup heating systems, which increases the cost and ...