thermal comfort

Night sky radiative cooling technology using PhotoVoltaic/Thermal panels (PVT) and night time ventilation have been studied both by means of simulations and experiments to evaluate their potential and to validate the created simulation model used to describe it. An experimental setup has been constructed at the Technical University of Denmark, where the outside PVT panels are connected through a storage tank to in-room radiant ceiling panels. The radiant ceiling panels include phase change material (PCM) and embedded pipes for circulating water.

Indoor temperature and humidity conditions as well as CO2 and airborne mould concentrations were measured in four manor schools in the Estonian cold climate. Based on these measurements, the influence of the indoor climate on the performance of schoolwork was assessed. The indoor environmental quality in manor schools turned out to be quite poor due to the inadequate performance of ventilation and heating systems. Intermittent stove heating was found to secure the minimum temperature in general but in winter thermal comfort was not always guaranteed.

Adequate ventilation is necessary to maintain thermal comfort and remove indoor air pollutant concentrations (Crump et al., 2005). Indoor pollutant concentrations vary considerably depending on occupants’ behaviour patterns, building characteristics and meteorological parameters and seasonal effects. Experimental measurements are time consuming and expensive to carry out, while computational models are regarded as a valid complement.

Building integrated renewable energy sources e.g. photovoltaic system is one of the promised solution for improving energy efficiency in building. However such kind of the system is restrained by irregular power supplied and necessity to convert current from direct to altering form. Therefore, very often the electrical energy generated by photovoltaic system cannot be effectively utilised to supply building devices, e.g. components of HVAC or lighting system.

To realize the concept of low-energy buildings, an increase in the thermal insulation performance of building parts, especially the openings that show poor insulation performance, is necessary. In addition, an adequate level of thermal comfort is also needed within residential buildings. We have developed window-applied dynamic insulation (DI), and verified thermal insulation performance in chamber and field tests.

The article describes the results of an experimental campaign carried out at ITC-CNR in outdoor test cells to evaluate the energy performance and the related comfort level achieved through a coupled system made up of a dynamic window and a heat recovery unit.

In recent years there has been much emphasis on improving the energy performance of Irish buildings. Much of this impetus stems from our requirements to implement provisions in the Energy Performance Building Directive (EPBD, 2002/91/EC, 2010/31/EU), and international targets to reduce CO2 emissions by 2020. In Ireland, residential buildings account for 27% of Ireland’s CO2 emissions after transport. As a large proportion of the Irish building stock has already been built home owners are encouraged to retrofit existing buildings to improve the energy rating.

A new school building block in Passivehouse standard near Kortrijk (Belgium) is in use since spring 2013. The urban development regulations required that this new building did not influence the incidence of daylight in the adjacent dwellings. This results in an open corridor on the first floor and classrooms with a front door. Draught and increased energy losses are expected. This design choice is contradictory to the basic idea of a passive school that aims to be very airtight and to have very low energy use and excellent thermal comfort.

The Kindergarten Solhuset is built according to the Active House vision with an emphasize of good daylight conditions and fresh air. The house was completed in 2011, and detailed measurements of the indoor environment have been performed since the completion. The daylight performance is evaluated with daylight factor simulations. The main activity rooms have daylight factors of 7%, while the innermost rooms with only roof windows achieve a high daylight factor of 4%. Electrical light is used frequently in daytime during the winter, but much less frequently during summer.

The effect of a cooling jet from ceiling on thermal comfort, perception and subjective performance in warm office environment (29.5 °C) was studied. Altogether, 29 participants (13 male and 16 female) participated. All participants were tested in both thermal conditions and the order of the thermal conditions was counterbalanced between the participants. During the experiment, participants filled questionnaires and performed computerised tasks. Using the cooling jet significantly improved the whole body and local thermal comfort.