Underfloor Heating Using Room Air Conditioners with Air Source Heat Pump in a Foundation Insulation House

Hiroki Ikeda,Yasushi Ooi,Takashi Nakaya

doi:10.3390/en14217034

Abstract

A good thermal environment is important in a place where occupants stay for a long time. Since heating a house consumes a lot of energy, an energy-efficient heating method will be required. Then, by combining a heat pump and underfloor heating, there is a possibility that both thermal comfort and energy saving can be achieved. The survey was conducted on a detached house located in Nagano Prefecture, Japan. The average outside air temperature was 4.2 °C. This study investigated the indoor thermal environment, evaluated the operating performance of the heat pump, and calculated the heat load by two-dimensional analysis. More than 80% of the subjects were satisfied with the thermal environment and the neutral temperature was 18.9 °C. In the operation of the heat pump, defrost operation was confirmed, but the average COP was 2.9, and it operated efficiently. In addition, the heat loss from the foundation slab was examined. Proper insulation placement has shown the potential to reduce heat loss. In conclusion, the use of heat pumps as a heat source has been shown to be efficient even in cold climates, and this study supports the construction of new heating methods.

Highlights

In an indoor environment, it is desirable to maintain the thermal comfort of occupants
There is no need to arrange ducts, and room air conditioners equipped with an air heat source heat pump can be used as air conditioning equipment
When heating using an air source heat pump, frost may form on the evaporator, which can reduce its heat exchange capacity

Summary

Introduction

It is desirable to maintain the thermal comfort of occupants. Local thermal environments, such as vertical air temperature differences and floor surface temperatures, affect the thermal comfort of occupants [1,2]. It is expected that the heated crawl space can be treated in the same way as indoors. A heating method has been proposed in which the heated crawl space is used as an air movement path. The crawl space heating raises the floor surface temperature and can reduce the local thermal discomfort at the feet. The combination of crawl space heating and air source heat pump has the potential to provide both thermal comfort and energy savings

Methods

Results

Conclusion