Numerical Investigation of Floor Heating Systems in Low Energy Houses

Peter Weitzmann, Jesper Kragh, Claus Franceos Jensen

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

Abstract

In this paper an investigation of floor heating systems is performed with respect to heating demand and room temperature. Presently (2001) no commercially available building simulation programs that can be used to evaluate heating demand and thermal comfort in buildings with building integrated heating and cooling systems exist. In Denmark over 80 % of all new single-family houses are using the building integrated floor heating systems. Therefore methods to evaluate building integrated heating must be developed. To examine this a simulation model of a room with floor heating has been created. The model calculates heating demand, room temperatures, and thermal comfort parameters for a person in the room. The model is based on a numerical Finite Control Volume (FCV) method for the heat transfer in walls, ceiling, windows and floor. The model uses both convective and radiative heat transfer to the room air and between the room surfaces. The simulation model has been used to calculate heating demand and room temperature in a typical well insulated Danish single-family house with a heating demand of approximately 6000 kWh per year, for a 130 m² house. Two different types of floor heating systems – a heavy system integrated into the concrete floor and a light system which is placed in heat transfer plates – have been investigated, using different supply temperatures to the floor heating system, and different control strategies. The aim of the study is to compare the two types of floor heating systems and various control strategies. The results are compared to an ideally heated room where the temperature is perfectly controlled. Another aim is to quantify the effect of comfort heating of floors with ceramic tiles. Comfort heating is defined by a wish to maintain a comfortable surface temperature of the floor of approximately 24 °C, even during the summer period where there is no heating demand. The results of the investigation show an increased heating demand when floor heating systems are compared to an ideal heating system. This larger heating demand is a consequence of imperfect control, increased heat loss to the ground and also increased operative room temperature. Only relatively small differences in the heating demand have been found when comparing the two different types of floors. The supply temperature and control strategy account for differences in the heating demand. When looking at the differences in the heating demand with different supply temperature and control strategy, it is however, important to notice that the differences is mainly due to differences in the resulting room temperature. When looking at comfort heating during the summer period, it can be seen that there is a large extra consumption of energy. Finally it can be noted, that an energy saving potential of up to 5 % exists when using a lower set point temperature in the night time.
Original languageEnglish
Title of host publicationProceedings of the 6th symposium on building physics in the nordic countries
Volume2
Publication date2002
Pages905-912
ISBN (Print)82-91412-02-2
Publication statusPublished - 2002
Event6th Symposium on Building Physics in the Nordic Countries - Trondheim, Norway
Duration: 17 Jun 200219 Jun 2002
Conference number: 6

Conference

Conference6th Symposium on Building Physics in the Nordic Countries
Number6
CountryNorway
CityTrondheim
Period17/06/200219/06/2002

Cite this

Weitzmann, P., Kragh, J., & Jensen, C. F. (2002). Numerical Investigation of Floor Heating Systems in Low Energy Houses. In Proceedings of the 6th symposium on building physics in the nordic countries (Vol. 2, pp. 905-912)