Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Ground-source heat pumps and energy saving
Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.ORCID iD: 0000-0002-7930-7894
2012 (English)In: Heat Exchangers: Basics Design Applications, IN-TECH, 2012Chapter in book (Refereed)
Abstract [en]

The global warming itself and its consequences cause considerable problems. It results in extreme climate events such as droughts, floods, or hurricanes, which are expected to become more frequent. This puts extra strain on people and has great impact on public health and life quality especially in poor countries. Internationally, there is a political understanding that global warming (or climate change) is the main challenge of the world for decades to come. Thus, all states must work together in order to overcome climatic change consequences. Although, studies suggest that there is indeed relationship between solar variability and global warming (Lean and Rind, 2001), two causes of the warming have been suggested: 1. related to the accumulation of greenhouse gases in the Earth’s atmosphere; 2. related to heat emissions (Nordell, 2003, Nordell and Gervet, 2009). This implies that current warming is anthropogenic and caused by human activities, i.e. global use of non-renewable energy. So far, the total global energy consumption has already exceeded 15.1010 MWh/year and it is projected to have an annual growth rate about 1.4 % until 2020 (EIA, 2010). Much of the energy used worldwide is mainly supplied by fossil fuels (~85 % of the global energy demand while renewable energy sources supply only about 6 %) (Moomaw et al., 2011, Jaber et al., 2011). Consequently, about 3.1010 ton of carbon dioxide emissions are annualllt emitted into the atmosphere. In other word, for each consumed kWh about 205 kg of carbon dioxide is being emitted into the atmosphere. Observations provide evidence that rising atmospheric CO2 level, which has increased by 25% last century caused by human activities, are associated with rising global temperature. There is mounting evidence that the mean global temperature has increased over the period 1880 to 1985 by 0.5 to 0.7 oC (Hansen and Lebedeff, 1987). While surface air temperature (SAT) compilations shows that SAT has increased 1.2 oC last century. If a current climatic change trend continues, climate models predict that the average global temperature are likely to have risen by 4 to 6 oC by the end of 21st century (Gaterell, 2005). Owing to the awareness of the impact of global warming and its relationship with human activities, there has been a growing interest in reducing fossil energy consumptions. Specifically, more efficient use of energy and increased use of renewable energy seem to be our main weapon against the ongoing global warming. In addition, as oil is a finite natural resource and subject to depletion, the oil price will increase and become more unstable and, consequently, economic risks will arise and economic grow rates will become unstable too. In another word, reducing our primary energy use as well as switching to a renewable energy system seem to be an urgent issue in order to have a stable future. Heating and cooling in the industrial, commercial, and domestic sectors accounts for about 40-50 % of the world’s total delivered energy consumption (IEA, 2007, Seyboth et al., 2008). Although, buildings regulations aim to reduce the thermal loads of buildings, as the economic growth improves standards of living, the energy demand for heating and cooling is projected to increase. For example, in non-OECD nations, as developing nations mature, the amount of energy used in buildings sector is rapidly increasing. Consequently, the implementation of more efficient heating/cooling systems is of clear potential to save energy and environment. However, the use of renewable energy systems for heating and cooling applications has received relatively little attention compared with other applications such as renewable electricity or biofuels for transportation. Yet, renewable energy sources supply only around 2-3% of annual global heating and cooling (EIA, 2010). Nowadays, heat pump systems are getting more common for heating and cooling purposes. Such system extracts energy from a relatively cold source to be injected into the conditioned space in winter or alternatively, extracts energy from conditioned spaces to be injected into a relatively warm sink in summer. The temperature difference between the conditioned space and the heat source/sink is referred to as temperature lift. This temperature plays a major role in determining the coefficient of performance (COP=delivered energy/driving energy) of heat pump systems. As temperature lift drops, the performance of the heat pump rises. More specifically, extracting heat from a warmer source during the winter and injecting heat into a colder source during the summer leads to a better COP and, consequently, less energy use. The ground temperature below a certain depth is constant over the year. This depth depends on the thermal properties of the ground, but it is in range of 10-15 m. Thus, the ground is warmer than the air during wintertime and colder than the air during the summertime. Therefore, using the ground, instead of the air, as heat source or as a heat sink for the heat pump results in smaller lift temperature. This fact represents the theoretical base of GSHP. The GSHPs move heat from the ground, i.e. solar energy that is naturally stored in the ground, to heat buildings in wintertime or alternatively, to cool them in summertime. This heat transfer process is achieved by circulating a heat carrier (water or a water–antifreeze mixture) between a ground heat exchanger (GHE) and heat pump condenser (summer time) or evaporator (winter time). The GHE is a pipe (usually of plastic) buried vertically or horizontally under the ground surface. Due to its high thermal performance, the ground source heat pump (GSHP) have increasingly replaced conventional heating and cooling systems around the world. Current work emphasizes the importance of using ground source heat pumps in reaching towards the renewable energy goals of climate change mitigation, and reduced environmental impacts.

Place, publisher, year, edition, pages
IN-TECH, 2012.
National Category
Water Engineering
Research subject
Water Resources Engineering
Identifiers
URN: urn:nbn:se:ltu:diva-20202Local ID: 2c9f9356-8991-4f0f-8aba-8b31bbe702e3ISBN: 9789535102786 (electronic)OAI: oai:DiVA.org:ltu-20202DiVA, id: diva2:993246
Note
Godkänd; 2012; 20110927 (khamoh)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-05-31Bibliographically approved

Open Access in DiVA

No full text in DiVA

Authority records BETA

Kharseh, Mohamad

Search in DiVA

By author/editor
Kharseh, Mohamad
By organisation
Architecture and Water
Water Engineering

Search outside of DiVA

GoogleGoogle Scholar

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 171 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf