hig.sePublikationer
Ändra sökning
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • sv-SE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • de-DE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Conversion of Electric Heating in Buildings: an Unconventional Alternative
Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för inomhusmiljö.
2008 (Engelska)Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 40, nr 12, s. 2188-2195Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

To decrease the electric energy used for heating buildings it has become desirable to convert direct electrical heating to other heat sources. This paper reports on a study of the possibility of using an unconventional method for conversion to avoid installing an expensive hydronic system. The conversion method combines the ventilation and heating systems and uses air instead of water for distribution of heat within the building, taking advantage of thermal forces and the special properties of gravity currents. Full-scale tests have been carried out in a test apartment inside a laboratory hall where the conditions could be controlled. Temperatures and efficiency of ventilation have been measured to ensure that the demands with respect to thermal climate and air exchange were fulfilled. The results show that it is possible to use the method for heating and ventilation when converting the heating system, but further work has to be done to develop a detailed solution that works in practice.

Ort, förlag, år, upplaga, sidor
2008. Vol. 40, nr 12, s. 2188-2195
Nyckelord [en]
thermal forces, large openings, gravity currents, electrical heating, conversion, heat transfer, district heating
Nationell ämneskategori
Energisystem
Identifikatorer
URN: urn:nbn:se:hig:diva-2006DOI: 10.1016/j.enbuild.2008.06.012ISI: 000260276200010Scopus ID: 2-s2.0-52149112514OAI: oai:DiVA.org:hig-2006DiVA, id: diva2:118668
Tillgänglig från: 2008-09-26 Skapad: 2008-09-26 Senast uppdaterad: 2018-03-13Bibliografiskt granskad
Ingår i avhandling
1. Distribution of Ventilation Air and Heat by Buoyancy Forces inside Buildings: an Experimental Study
Öppna denna publikation i ny flik eller fönster >>Distribution of Ventilation Air and Heat by Buoyancy Forces inside Buildings: an Experimental Study
2009 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

The main task of the ventilation system in a building is to maintain the air quality and (together with the heating or cooling system) the thermal climate at an acceptable level within the building. This means that a sufficient amount of ventilation air at the appropriate temperature and quality must be supplied to satisfy thermal comfort and air quality demands and that this air is distributed to the parts of the building where people reside. Air movements caused by buoyancy forces can determine the distribution of ventilation air within buildings. The purpose of this thesis is to advance the state of knowledge of buoyancy-driven air movements within buildings and to determine their importance both for ventilation air distribution and the maintenance of thermal comfort and air quality in buildings. The work is focused on studying thermally-driven air movements through large openings, both horizontal and vertical (i.e. doorways). The properties of a special type of thermally-driven currents, so called gravity currents, have also been explored. Large vertical openings like doorways are important for air exchange between rooms within a building. Air movements through doorways separating rooms with different air temperatures are often bidirectional and the buoyancy-driven flow rates are often greater than those caused by the mechanical ventilation system alone. Bidirectional flows through doorways can effectively spread contaminants, for example, from a kitchen or a hospital rooms, yet the results of this study indicate that the conversion of a thermally-driven bidirectional flow to a unidirectional flow via an increase of the mechanically forced flow rate requires forced flows that are more than three times greater than the thermally-driven flows. Experiments conducted in this project indicate that the resistance to buoyancy-driven flows in horizontal openings is significantly greater than that in vertical openings. Model tests have shown, however, that this problem may be mitigated if a simple model of a staircase located in the centre of the room (being ventilated) is linked to the horizontal ventilation opening. Gravity currents in rooms occur in connection with so called displacement ventilation as cool gravity currents propagate along the floor that are driven by the density difference of the ventilation air and the ambient, warmer air within the room. As these gravity currents easily pass obstacles and to a certain extent are self-controlling, they can effectively distribute the cool air within rooms in a building. Likewise, warm gravity currents occur when warmer air introduced in a room rises and spreads along the ceiling plane. One application where warm gravity currents may be used to advantage is when converting buildings from electric heating to district hot water heating thus, avoiding the introduction of an expensive hydronic heating system. This report includes a full-scale laboratory study of the basic properties of thermally-driven warm air gravity currents in a residential building and examines the possibilities of using the resulting air movements for the distribution of ventilation air as well as heat. Results from laboratory tests show that this conversion method may prove effective if certain conditions on the layout of the building are fulfilled.

Ort, förlag, år, upplaga, sidor
Stockholm: KTH, 2009. s. xi, 56
Nyckelord
building ventilation, thermal forces, buoyancy, gravity currents, large openings, heating, air quality, forced convection, free convection
Nationell ämneskategori
Husbyggnad
Identifikatorer
urn:nbn:se:hig:diva-4550 (URN)978-91-7415-322-4 (ISBN)
Disputation
2009-06-09, 33:202, Kungsbäcksvägen 47, Gävle, 10:15 (Svenska)
Opponent
Handledare
Tillgänglig från: 2009-06-14 Skapad: 2009-06-05 Senast uppdaterad: 2018-03-13Bibliografiskt granskad

Open Access i DiVA

Fulltext saknas i DiVA

Övriga länkar

Förlagets fulltextScopus

Personposter BETA

Blomqvist, Claes

Sök vidare i DiVA

Av författaren/redaktören
Blomqvist, Claes
Av organisationen
Ämnesavdelningen för inomhusmiljö
I samma tidskrift
Energy and Buildings
Energisystem

Sök vidare utanför DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetricpoäng

doi
urn-nbn
Totalt: 179 träffar
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • sv-SE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • de-DE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf