heating

Productivity of workers is greatly affected by their comfort in the workplace. Research has shown that thermal comfort is one of the most influential parameters on worker productivity, and that the running costs of a Heating, Ventilation and Air Conditioning (HVAC) system could be up to ten times lower compared to productivity losses that would be incurred in a free-runing building.

This study aims at obtaining feedback from occupants of low-energy retrofitted houses concerning the indoor environmental quality (IEQ) and the building systems in their homes. A questionnaire study was carried out in a social housing complex consisting of 2007 single-family houses, of which 1305 were retrofitted between 2014 and 2019. The different retrofitted houses were equipped with two types of heating systems, as well as balanced mechanical ventilation with two inlet locations.

Renewable energy sources for heating and cooling buildings usually have temperatures close to room temperature and therefore a limited convertibility potential, i.e. they are of low value. To exploit low-valued energy sources Low Temperature Heating and High Temperature Cooling (LTH-HTC) systems must be developed.

Very often the set point temperature is selected to satisfy comfort requirements and/or to save energy consumption in buildings. However, the thermostat location is usually outside the occupied space and located on the wall near a front door or in a hallway that is subject to warm and cold draughts. A discrepancy exists between the temperature at the thermostat location and the occupied zones.

The paper investigates the possibility for using a traditional ventilation system with ceiling mounted diffusers to provide heating under winter time conditions in relatively cold climates – in buildings with low transmition losses such as “passive houses”. The analysis is done through a number of CFD simulations of a simplified office. It is shown that even small over-temperatures reduce the Air Change Efficiency substantially. On the other hand even very small internal heat sources increase the efficiency.

In this article we compare to ventilation strategies to heat a “passive house” office building using only the ventilation system. Two ventilation strategies with supply air temperature above and below the current room temperature were compared through a cross over experiment. A questionnaire was used to measure the perceived health and well being. Both strategies documented very good indoor climate with highly positive scores on the questionnaire.

This paper explores the developing process and resulting features of an ultra high performance tower designed by Skidmore, Owings and Merrill through a multidisciplinary approach to building simulation and analysis. The 309 meter tall office tower for a new development in the Pearl River Delta region of Southern China, is an exemplar of the marriage of technical sophistication with a graceful form, featuring integrated renewable energy strategies and an active double skin facade coupled with a low energy building conditioning system.

Failures can lead to a series of problems in the complex heating, ventilation and air-conditioning (HVAC) systems in buildings. Fault detection and diagnosis (FDD) is an important technology to solve these problems. Models can represent the behaviors of the HVAC systems, and FDD can be realized with models. Using the model as intermediary, a link between system simulation and FDD can be built. Simulation has provided a convenient platform of operation for FDD, the overall simulation methodology in FDD of HVAC systems is briefly introduced.

A new set of climatic data for different kinds of calculations has been compiled for various Swiss localities. This includes the generation of new design reference year data sets with hourly values for e.g. building simulations. The procedure conforms to a set of new European standards describing the algorithms. One key element in this is the processing of solar radiation information, especially for the separation into direct and diffuse components. The most advanced methodology was used.

This paper explores the simulation of the thermal performance of a radiant floor for heating and cooling that is connected with an underground heat exchanger installed under the concrete floor of a house. In the heating season, an electric boiler is used to maintain the operative temperature at the set point value by varying the supply water temperature to the radiant slab. In the cooling season, the water from the radiant floor is circulated through an underground heat exchanger installed under the concrete slab.