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ASHRAE LO-09-053
Comparison Between a Radiant Floor and Two Radiant Walls on Heating and Cooling Energy Demand
Year: 2009
Abstract: INTRODUCTION
Radiant systems became very popular in the last decades. They are commonly used as radiant floor systems, although from the 1990s radiant ceilings have been increasingly installed. In the last years several producers propose radiant wall systems: these systems have some inconvenient when hanging pictures, as well as problems with furniture. Wall systems have an overall heat exchange coefficient equal to 8 W/(m2·K) (1.41 Btu/[h·ft2·°F]) both in heating and cooling conditions (CEN 2008). Radiant floor systems have an overall heat exchange coefficient equal to 11 W/(m2·K) (1.94 Btu/ (h·ft2·°F)) in heating and equal to 7 W/(m·2K) (1.23 Btu/ (h·ft2·°F)) in cooling conditions.
Many times manufacturers of radiant wall systems propose their application directly on external walls. In this case insulation behind pipes has to be applied, since, otherwise, losses become very high.
Since it does not seem clear the entity of the losses when applying a radiant floor or a radiant wall heating, in this work a comparison between those systems has been carried out; moreover the influence of position of insulation layer in radiant wall systems has been analyzed.
A comparison between different systems is almost impossible to carry out by means of measurements, since many uncertainties appear when measuring energy performance in buildings. Therefore the recourse to a dynamic simulation with detailed models seems inevitable when comparing different systems under the same conditions.
A suitable model should take into account the internal loads, solar radiation, as well as thermal conduction in transient conditions inside structures where pipes are embedded. Many models have been proposed in the last years. In this work the model DigiThon (Brunello et al. 2001) has been used. Such a model is based on transfer function method (Kusuda 1969, De Carli 2002), and it allows simulating which-ever radiant system, since transfer functions can be calculated via two-dimension detailed model (Blomberg 1999).
In this way it is possible to evaluate hour by hour the energy demand of the radiant wall, both as useful thermal energy for the house and losses behind pipes.
Radiant systems became very popular in the last decades. They are commonly used as radiant floor systems, although from the 1990s radiant ceilings have been increasingly installed. In the last years several producers propose radiant wall systems: these systems have some inconvenient when hanging pictures, as well as problems with furniture. Wall systems have an overall heat exchange coefficient equal to 8 W/(m2·K) (1.41 Btu/[h·ft2·°F]) both in heating and cooling conditions (CEN 2008). Radiant floor systems have an overall heat exchange coefficient equal to 11 W/(m2·K) (1.94 Btu/ (h·ft2·°F)) in heating and equal to 7 W/(m·2K) (1.23 Btu/ (h·ft2·°F)) in cooling conditions.
Many times manufacturers of radiant wall systems propose their application directly on external walls. In this case insulation behind pipes has to be applied, since, otherwise, losses become very high.
Since it does not seem clear the entity of the losses when applying a radiant floor or a radiant wall heating, in this work a comparison between those systems has been carried out; moreover the influence of position of insulation layer in radiant wall systems has been analyzed.
A comparison between different systems is almost impossible to carry out by means of measurements, since many uncertainties appear when measuring energy performance in buildings. Therefore the recourse to a dynamic simulation with detailed models seems inevitable when comparing different systems under the same conditions.
A suitable model should take into account the internal loads, solar radiation, as well as thermal conduction in transient conditions inside structures where pipes are embedded. Many models have been proposed in the last years. In this work the model DigiThon (Brunello et al. 2001) has been used. Such a model is based on transfer function method (Kusuda 1969, De Carli 2002), and it allows simulating which-ever radiant system, since transfer functions can be calculated via two-dimension detailed model (Blomberg 1999).
In this way it is possible to evaluate hour by hour the energy demand of the radiant wall, both as useful thermal energy for the house and losses behind pipes.
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ASHRAE LO-09-053
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| contributor author | ASHRAE - American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. | |
| date accessioned | 2017-09-04T18:40:04Z | |
| date available | 2017-09-04T18:40:04Z | |
| date copyright | 01/01/2009 | |
| date issued | 2009 | |
| identifier other | JTYXPCAAAAAAAAAA.pdf | |
| identifier uri | http://yse.yabesh.ir/std;query=autho162sear79D/handle/yse/221800 | |
| description abstract | INTRODUCTION Radiant systems became very popular in the last decades. They are commonly used as radiant floor systems, although from the 1990s radiant ceilings have been increasingly installed. In the last years several producers propose radiant wall systems: these systems have some inconvenient when hanging pictures, as well as problems with furniture. Wall systems have an overall heat exchange coefficient equal to 8 W/(m2·K) (1.41 Btu/[h·ft2·°F]) both in heating and cooling conditions (CEN 2008). Radiant floor systems have an overall heat exchange coefficient equal to 11 W/(m2·K) (1.94 Btu/ (h·ft2·°F)) in heating and equal to 7 W/(m·2K) (1.23 Btu/ (h·ft2·°F)) in cooling conditions. Many times manufacturers of radiant wall systems propose their application directly on external walls. In this case insulation behind pipes has to be applied, since, otherwise, losses become very high. Since it does not seem clear the entity of the losses when applying a radiant floor or a radiant wall heating, in this work a comparison between those systems has been carried out; moreover the influence of position of insulation layer in radiant wall systems has been analyzed. A comparison between different systems is almost impossible to carry out by means of measurements, since many uncertainties appear when measuring energy performance in buildings. Therefore the recourse to a dynamic simulation with detailed models seems inevitable when comparing different systems under the same conditions. A suitable model should take into account the internal loads, solar radiation, as well as thermal conduction in transient conditions inside structures where pipes are embedded. Many models have been proposed in the last years. In this work the model DigiThon (Brunello et al. 2001) has been used. Such a model is based on transfer function method (Kusuda 1969, De Carli 2002), and it allows simulating which-ever radiant system, since transfer functions can be calculated via two-dimension detailed model (Blomberg 1999). In this way it is possible to evaluate hour by hour the energy demand of the radiant wall, both as useful thermal energy for the house and losses behind pipes. | |
| language | English | |
| title | ASHRAE LO-09-053 | num |
| title | Comparison Between a Radiant Floor and Two Radiant Walls on Heating and Cooling Energy Demand | en |
| type | standard | |
| page | 10 | |
| status | Active | |
| tree | ASHRAE - American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.:;2009 | |
| contenttype | fulltext |