Heat Exchanger Technology : Energy Sources for Future (original) (raw)
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In the recent attempts to stimulate alternative energy sources for heating and cooling of buildings, emphasise has been put on utilisation of the ambient energy from ground source heat pump systems (GSHPs) and other renewable energy sources. Exploitation of renewable energy sources and particularly ground heat in buildings can significantly contribute towards reducing dependency on fossil fuels. Geothermal heat pumps (GSHPs), or direct expansion (DX) ground source heat pumps, are a highly efficient renewable energy technology, which uses the earth, groundwater or surface water as a heat source when operating in heating mode or as a heat sink when operating in a cooling mode. It is receiving increasing interest because of its potential to reduce primary energy consumption and thus reduce emissions of the greenhouse gases (GHGs). The main concept of this technology is that it utilises the lower temperature of the ground (approximately <32°C), which remains relatively stable throughout the year, to provide space heating, cooling and domestic hot water inside the building area. The main goal of this study is to stimulate the uptake of the GSHPs. Recent attempts to stimulate alternative energy sources for heating and cooling of buildings has emphasised the utilisation of the ambient energy from ground source and other renewable energy sources. The purpose of this study, however, is to examine the means of reduction of energy consumption in buildings, identify GSHPs as an environmental friendly technology able to provide efficient utilisation of energy in the buildings sector, promote using GSHPs applications as an optimum means of heating and cooling, and to present typical applications and recent advances of the DX GSHPs. The study highlighted the potential energy saving that could be achieved with ground energy sources. It also focuses on the optimisation and improvement of the operation conditions of the heat cycle and performance of the DX GSHP. It is concluded that the direct expansion of the GSHP, combined with the ground heat exchanger in foundation piles and the seasonal thermal energy storage from solar thermal collectors, is extendable to applications that are more comprehensive.
Environmental Progress & Sustainable Energy, 2017
Owing to the eye-catching pros of high energy and environmental performances, numerous ground-source heat pump (GSHP) systems have been employed in domestic and industrial buildings throughout the world. One of the proved renewable energy technologies is the GSHPs which is able to fulfill the gap between cooling and heating. The main contribution of this article is to present a fully description and critical review of the GSHP systems along with their current developments. At first, the energy efficiency and working standard of a heat pump are introduced. Furthermore, an expansive description of the GSHPs and its advances, and a fully explanation of the ground-couplet (GCHP) heat pumps, groundwater (GWHP), and surface water (SWHP) are provided. The mainly representative ground thermal response examination approaches and simulation for the vertical ground heat exchangers presently existing are reviewed counting the heat transfer progressions inside and outside the holes. Similarly, various info regarding a different GWHP by a heat exchanger with different structures, and the opportunity to gain the enhanced energy efficiency with joint cooling and heating using GCHP are explained. The numerous hybrid GCHP systems for heating or coolingdominated constructions are appropriately illustrated. It can be deduced that the GSHP technology can be employed both in hot and cold weather areas and the potential of energy saving is noteworthy. V
Experimental Performance Analysis of Ground Source Heat Pumps (GSHPs)
2018
Ground Source Heat Pumps (GSHP) have become as one of the most indispensable cooling and heating systems in residential applications since they have higher energy efficiency compared to the other conventional alternatives all around the world. In this study, a ground source heat pump system (GSHP) with the heat package unit model of GT018 FHP Manufacturing Co., was installed. The system setup included polyethylene U-bend ground heat exchanger pipes, nine drilled wells, and the pipes buried in soil at 15 m depth and in the cooling season of 2013. The system was tested, and its performance was reported. By the meteorological data, the values of humidity variations, air temperature, wells and water temperatures, relative humidity, and the system power supply were measured continuously for three months. The results showed that the adoption of GSHP system created a stable room indoor temperature of 25°C to 28°C. Furthermore, a great energy saving happened in the process, and the average ...
THERMAL PERFORMANCES OF DIFFERENT TYPES OF UNDERGROUND HEAT EXCHANGERS
Globally buildings are responsible for approximately 40% of the total world annual energy consumption. Most of this energy is for the provision of lighting, heating, cooling and air conditioning. An increase in awareness of the environmental impact of CO2, NOx and CFCs emissions triggered a renewed interest in environmentally friendly cooling and heating technologies. Under the 1997 Montreal Protocol, governments agreed to phase out chemicals used as refrigerants that have the potential to destroy stratospheric ozone. An approach is needed to integrate renewable energies in a way to achieve high building performance standards. However, because renewable energy sources are stochastic and geographically diffuse, their ability to match demand is determined by the adoption of one of the following two approaches: the utilisation of a capture area greater than that occupied by the community to be supplied, or the reduction of the community's energy demands to a level commensurate with the locally available renewable resources. Ground source heat pump (GSHP) systems (also referred to as geothermal heat pump systems, earth-energy systems and GeoExchange systems) have received considerable attention in recent decades as an alternative energy source for residential and commercial space heating and cooling applications. The GSHP applications are one of three categories of geothermal energy resources as defined by ASHRAE and include high-temperature (>150°C) for electric power production, intermediate temperature (<150°C) for direct-use applications and GSHP applications (generally (<32°C). The GSHP applications are distinguished from the others by the fact that they operate at relatively low temperatures.
Ground-source pump system for heating and cooling: Review and thermodynamic approach
Renewable and Sustainable Energy Reviews
Ground source heat pump (GSHP) is an innovative and perspective technology able to use the ground as a thermal sink or heat source. If combined with system operating at relatively low temperature, it represents a high efficiency solution for the heating of buildings. Complementarily, during cooling operation it has a good advantage with respect to air-cooled systems, because the ground temperature is stably lower than the outdoor air one. Geothermal heat pump systems are able to reduce the environmental impact of buildings for space heating and cooling by using the ground as an energy renewable source. This paper presents a review on the GSHP systems presenting both a summary of different ground-source typologies of heat pumps and a thermodynamic approach for their modeling. The irreversible thermodynamic approach is here summarized and exposed for a complete GSHPs system. This analytical approach is particularly useful for implementing an optimization design tool for GSHP systems. Recently many works have 2 been published about exergy analysis of these systems. Those works suggest that future lines of development may be considered: a) the optimization based on the transient performance of GSHP systems and not on the sole design condition; b) the integration of irreversible thermodynamic optimization approach into the algorithms of control systems. The diffusion of optimized GSHP systems is essential in order to reduce fossil fuel consumption and CO 2 emissions, complying with the EU's directive.
2008
Ground-source heat pump (GSHP) systems represent an energy efficient technology for heating and cooling of non-residential buildings due to the relatively high and stable heat source temperature and the fact that a considerable share of the cooling demand can be covered by means of so-called "free cooling". Installation of high quality GSHP systems therefore complies with the main goals of the new EU Directive on The Energy Performance of Buildings (Directive 2002/91/EC), i.e. reduction of the total primary energy demand and the associated CO2 emissions in buildings. The paper discusses the main characteristics of GSHP systems for heating and cooling of non-residential buildings in Norway including operational experiences. Several high-quality GSHP systems are presented, including installations in office buildings and a hospital. The latter GSHP system is connected to one of the largest underground thermal energy storages in Europe comprising as many as 350 boreholes in cr...
Applied Thermal Engineering, 2015
A range of analytical and numerical models is available to investigate the thermal behaviour of vertical ground heat exchangers, both in the short-and long-term. However, most of them ignore the thermal effects of weather at ground level that affect the upper part of boreholes. Furthermore, few models look at the integrated simulation of a ground source heat pump system for both the borehole field and heat pump. Consequently, a limited number of applications to real cases are available for designers. This paper shows a study to assess the effects of both axial heat transfer in boreholes and the weather at ground level on the fluid temperature in the boreholes, as well as on the energy efficiency of the heat pump. To this purpose, long-term analysis of two ground source heat pump systems was conducted over ten years by means of a detailed