Adaptive comfort model incorporating temperature gradient for a UK residential building

Thermal comfort field experiments were conducted to acquire thermal comfort data of 119 participants in a test house representative of a typical UK house. This paper compares the performance of popular PMV-based thermal comfort index vs neutral temperature based on Actual Mean Vote. The aim of this research was to incorporate vertical thermal gradient, which is usually a neglected yet highly influential parameter in a residential setting and propose a new adaptive thermal comfort model. The new adaptive model (LPMV) has been developed using a polynomial curve fit method. This method was chosen as it has the capability to correlate indoor environmental parameters with AMV and incorporated them in the generated mathematical model. The model requires temperature gradient and SET* only to determine neutral temperatures which makes it the first of its kind. The LMPV model was rigorously tested against thermal comfort data compiled in this study and against independent/unbiased data (the ASHRAE RP-884 database). LPMV showed up to 0.7°C improvement in predicting neutral temperature of occupants compared to the famous Fanger’s PMV model. This can result in better prediction of a suitable heating setpoint temperature which has great implications on annual energy demand

Performance assessment of Fanger’s PMV in a UK residential building in heating season

Traditionally there are two approaches to thermal comfort studies in the indoor environment. The first approach is to conduct tests in fully controlled climate chambers located in laboratories which help in maintaining desired environmental conditions for the experiments. However, the thermal physics of climate chambers are very different to that of real buildings. Additionally, the numbers of participants in such studies are also limited. The alternate/second approach is to place sensors and collect data in a set of homes and offices over a period of time where researchers have virtually no control on the thermal environment. This approach does involve a large set of participants however the large variations in thermal environmental parameters make the data not very reliable to elucidate trends. This paper reports on an original approach that combines the advantages of both these methods. In this research thermal comfort studies were conducted in a test house representative of a real residential building and a large set of participants. The thermal environmental parameters and heating strategies inside the test house were also fully controlled by researchers. The aim was to assess the performance of Fanger’s thermal comfort model (PMV) in predicting the actual thermal comfort of occupants (AMV) during heating season using two different types of heating emitters. A total of 119 participants between the ages of 19 and 21 years took part in these experiments. AMV of the occupants was determined by conducting surveys whilst PMV was calculated using sensors installed in the living room. Thermal neutral temperatures were calculated and compared for both AMV and PMV indices. It was found that there is a strong and directly proportional relation of both AMV and PMV with the operative temperature in the room. It was also observed that PMV would typically overestimate the neutral temperature compared to the statistically derived neutral temperature which the occupants would consider thermally comfortable

Temperature sensitivity analysis of thermal comfort in a UK residential building

This research focusses on investigating the sensitivity of thermal comfort to temperature in a heated space. Thermal comfort test sessions are conducted in a test house representative of a typical UK house during the winter season. A total of 119 participants took part in the series of tests conducted in the test house’s living room. Operative temperature in the heated space was maintained within the comfortable range recommended by CIBSE for a living room area in a UK house. Two different heating emitters were used for heating during the tests in order to examine their effects on occupant thermal comfort. Conventional radiators supplemented by a gas boiler and an electric fan heater were investigated in the presence and absence of a circulation fan running in the corner of the room. Thermal comfort sensation of occupants was calculated using sensors installed in the living room (Fanger’s Predicted Mean Vote). At the same time the occupants were asked to fill in surveys which were used to record their Actual Mean Vote. From the test sessions conducted it was found that AMV predicted a neutral temperature of 23.5°C whilst PMV predicted a neutral temperature of 24.0°C thus PMV over predicted the occupant’s thermal sensation compared to AMV. For the four heating scenarios it was found that a convective fan heater with a circulation fan causes the smallest temperature gradient (1.0oC) between ankle and head height for a seated occupant according to ISO7730 standards. The highest temperature gradient was measured for fan heater without a circulation fan (7.3oC). Occupants reported to be most uncomfortable if the convector heater without a circulation fan was used