A hybrid photovoltaic solar assisted loop heat pipe/heat pump (PV-SALHP/HP) water heater system has been developed and numerically studied. The system is the combination of loop heat pipe (LHP) mode and heat pump (HP) mode, and the two modes can be run separately or compositely according to the weather conditions. The performances of independent heat pump (HP) mode and hybrid loop heat pipe/hea...

A possibility of increasing interest for reducing the energy consumption in office and health care buildings consist in better exploiting the potential of the heat pump technology. This can be done by recovering heat at the condenser when the chiller is used to produce cold (simultaneous heating and cooling demands) or by using the chiller in heat pump mode (non-simultaneous heating and cooling...

In recent years the heat fluxes that must be removed from terrestrial electrical systems have been steadily increasing. The same increase in electrical component heat flux can also be seen in satellite and aerospace applications. As a result, it has proven necessary to develop heat pump systems that can operate in low-gravity environments with high reliability and efficiency to cool electrical ...

Carbon dioxide is a safe, economic and environmentally sustainable refrigerantwhich can be used in heat pump and refrigeration systems. Research into the performance and benefits of a transcritical heat pump cycle using carbon dioxide began in the early 1990s. Theoretical and experimental research, as well as commercial system development, has improved transcritical system performance to a leve...

– We show that a mesoscopic system such as Feynman’s ratchet may operate as a heat pump, and clarify a underlying physical picture. We consider a system of a particle moving along an asymmetric periodic structure. When put into a contact with two distinct heat baths of equal temperature, the system transfers heat between two baths as the particle is dragged. We examine Onsager relation for the ...

A prototype compressor for application in high temperature compression-resorption heat pumps has been designed, manufactured and tested. The paper presents details of the compressor design together with test results obtained on the pilot heat pump plant with the prototype compressor. The compressor is of the twin-screw type and its stainless steel rotors operate without timing gears. There is n...

In China, for the limitation of land, many buildings intending to utilize ground source heat pump systems install “single-well” systems, which drill only one well for both the pumping and reinjection of the groundwater. A model of groundwater seepage and heat transfer for single-well ground source heat pump systems has been established and validated against the experiment conducted in Denmark. ...

This study evaluates the performance of air source heat pump (ASHP) and ground source heat pump (GSHP) systems individually and as part of their associated heating and cooling distribution systems in two semi-attached houses. Over the monitoring period, the performance of both heat pumps exceeded manufacturer and EnerGuide ratings, with Coefficients of Performance (COPs) above 5 in the cooling ...

An 11 kW R410A heat pump system with a two-stage vapor-injected scroll compressor has been developed and tested. A conventional heat pump system with a scroll compressor having the same displacement volume to the vapor-injected scroll compressor has been tested under the same conditions to serve as a baseline. The vaporinjected scroll compressor has been tested with the cycle options of both fl...

A benchmark analysis was conducted to predict the maximum steady-state pet$onnance potential of a nearterm moduikting residential-size heat pump. Continuousiy variable-speed, permane nt-magnet electronically commutated motors (ECMs) were assumed to modulate the compressor and the indoor and outdoor fans in conjunction with existing modulating reciprocating compressor technology A modulating hea...