The primary objective of a greenhouse is to produce good plant-growth conditions such as temperature and humidity. One of the hot issues for the greenhouse is to provide an appropriate heating system which can achieve favorable temperature condition and save energy. In this study, the...

Heat pump systems offer economical alternatives for recovering heat from different sources for use in domestic and industrial refrigeration, space heating, and air conditioning. Some of these domestic and industrial applications require very low evaporating temperatures and very high condensing...

Energy foundations and other thermo-active ground structure, energy wells, energy slabs, and pavement heating and cooling represent an innovative technology that contributes to environmental protection and provides substantial long-term cost savings and minimized maintenance. This paper focuses...

To make an energy efficient GSHP system, the heat pump unit should have high efficiency and be optimized well with other parts such as ground heat exchangers and pumps. The amount of refrigerant charge in the heat pump unit is one of the primary parameters influencing system performance. In the...

Heat pump systems have been widely used in buildings and industries due to their high performance. In this study, a leaving water temperature control scheme has been proposed for a water-to-water heat pump for hot water supply. The study was focused on the following four schemes: (1) using an...

The effective thermal conductivity of six vertical closed-loop ground heat exchangers (GHEXs), which were installed in a test bed located in Wonju, South Korea, has been experimentally evaluated by performing in-situ thermal response tests (TRTs). To compare the thermal efficiency of the GHEXs...

In the present study, the performance of a heat pump unit is measured by varying the secondary fluid flow rate and compressor speed. Test results are applied to design the GCHP system, and then the effects of the flow rate and the thermal conductivity on the performance of the system and the...

The main solution for the reduction of energy consumption in the field of HVAC is the development of new and renewable energy technologies. Among the various renewable energy systems, ground source heat pump (GSHP) systems have been spotlighted as efficient building energy systems because of...

Heat pumps, as a process recirculating environmental heat back into useful heat production, fit the environmental requirements of present global policy. They are very useful tools to reduce the need of fossil fuels in space heating and cooling. The government of the Republic of Korea has...

Heat pumps have been spotlighted as efficient building energy systems because they have great potentials for energy reduction in building air conditioning and reducing CO2 emission. In this study, a multi-function heat pump which has the functions of heating, cooling, and hot water supply was...