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Introduction
Published in Hui Huang, Heat Pumps for Cold Climate Heating, 2020
Hui Huang, Xiangfei Liang, Bo Zheng
A heat pump is a device that transfers thermal energy from a heat source to a heat sink. The heat pump cycle shares the same thermodynamic principle with the refrigeration cycle, however, it brings different effects from the refrigeration cycle. For example, the heat pump cycle absorbs heat from the outdoor environment (low temperature heat source) and releases heat to the indoor environment (high temperature heat sink), which results in the indoor temperature increasing and keeping it higher than the outdoor temperature. However, the refrigeration cycle absorbs heat from the indoor environment (low temperature heat source) and releases heat to the outdoor environment (high temperature heat sink), which results in the indoor temperature decreasing and keeping it lower than the outdoor temperature.
Lakes as a heat source for heat pumps – a model study to determine the ecological impact of summer heat transfer
Published in Jochen Bundschuh, Guangnan Chen, D. Chandrasekharam, Janusz Piechocki, Geothermal, Wind and Solar Energy Applications in Agriculture and Aquaculture, 2017
Renata Brzozowska, Maciej Neugebauer, Janusz Piechocki
A heat pump is a device, the function of which is to extract heat from a source at a lower temperature (lower) and transfer it to a target at a higher temperature (upper). To make this achievable, it is necessary to provide the operating power for the heat pump, since the spontaneous flow of heat from a lower temperature body to a higher temperature body is not possible. The ratio of heat given back into the upper source to the energy needed to drive the heat pump is always greater than one. The efficiency of an ideal heat pump depends on the temperature difference of the two heat sources. The smaller it is, the more efficiently the pump is working (Zawadzki, 2003). Heat pumps can be divided into three types:Compressor heat pumpThermoelectric heat pumpAbsorption heat pump.Heat pumps belonging to the first group are the most commonly used in space heating (Kavanaugh and Rafferty, 2014; Petit and Collins, 2011; Rubik, 2011).
Heat Pumps
Published in Frank Jackson, Dilwyn Jenkins, Renewable Energy Systems, 2013
Installing a heat pump can help you save a significant amount of energy and money, but they can also be useful in reducing a household’s or business’s carbon footprint. The low-grade heat they utilise is considered to be a renewable resource, and although they do require electricity (which usually comes from non-renewable fossil-fuel sources) the high efficiencies can make the CO2emissions per unit of heat delivered considerably lower on average for heat pumps than for other heating systems. If a renewable source of electricity is used, CO2emissions can be reduced to almost zero. Many fossil-fuel-based electricity companies offer a ‘green tariff’ (this means your bill is paying for a proportional amount of renewable energy to enter the grid) which you can sign up for if you wish to maximise the carbon savings of your installation.
The United Nations World Water Development Report 2022 on groundwater, a synthesis
Published in LHB, 2022
Large modern buildings (offices, data centres, hospitals, etc.) have a large cooling requirement, even in winter and in temperate climates. Many industrial processes also have cooling requirements, and the need for low-carbon cooling will likely increase as climate change progresses. Cool shallow groundwater (e.g. 10–12°C in many parts of the United Kingdom) is well suited for receiving surplus heat and effecting cooling, via a well doublet arrangement. Cool shallow groundwater can also be used for heating via ground source heat pumps. A heat pump is an electrically powered refrigerant device that transfers heat from a cold medium (e.g. groundwater at 10°C) to a warm medium (e.g. a central heating system at 45°C). Although wind and solar technologies can generate low-carbon electricity, relatively few technologies exist to provide low-carbon heating. The heat pump is a key technology that utilises electricity highly efficiently to deliver heating and cooling. It may be able to deliver 3.5 kW of heat to a building for every 1 kW of electrical power consumed, resulting in dramatic reductions in cost and CO2 emissions. As of 2020, around 6.5 million geothermal heat pumps are thought to be installed worldwide, representing the fastest growing part of the geothermal sector (112).
Monte Carlo simulation approach to understand the cost variance for energy retrofit projects: comparative study of Finland and the United States
Published in Construction Management and Economics, 2022
Ming Hu, Eero Nippala, Kari Kallioharju, Sofie Pelsmakers
The first cause refers specifically to the heat pump system. All projects included in the Finnish database have been retrofit with an energy-efficient heat pump system, using either a ground source or air source. The main benefits of a heat pump system are realized when the heat demand is high (such as in cold climates), which makes the heat pump system preferable as a highly energy-efficient heating system. Heat pump technologies have been utilized in Finland for several decades, and design and construction teams are equipped with the necessary knowledge to retrofit buildings with more energy-efficient systems. There have been many studies in Finland supporting the rapid adoption of the heat pump system. It was suggested that Finnish nearly zero energy buildings can be achieved more cost-efficiently from utilizing heat pumps rather than district heating (Häkämies et al. 2015).
Modeling of vertical ground heat exchangers
Published in International Journal of Green Energy, 2021
Seama Koohi-Fayegh, Marc A. Rosen
Heat pumps use the same mechanical principles as refrigerators. While refrigerators remove heat from the interior and discharge it to the environment, heat pumps take heat from the environment and concentrate it to heat the building in the summer. A heat pump is a machine that transfers heat from a source to another region by employing a refrigeration cycle. Although heat normally flows from higher to lower temperatures, a heat pump reverses that flow and acts as a “pump” to move the heat. Therefore, a heat pump can be used both for space heating in the winter and for cooling (air conditioning) in the summer. In the refrigeration cycle, a refrigerant (known as the “working fluid”) is compressed (as a liquid) then expanded (as a vapor) to absorb and remove heat. The heat pump transfers heat to a space to be heated during the winter period and, by reversing the operation, extracts (absorbs) heat from the same space to be cooled during the summer period.