Improvement of winter heat balance of workshops

Abstract

Abstract. The aim of this paper is to describe the principles and methods of heat balance calculation in winter, which can be useful for assessment and improvement of heat transmission in the building. There are set up formulas and calculated the required heating capacity in two workshops to keep the standard internal temperature (from 16 °C to 20 °C) for students' practice during a winter day with external temperature about -12 °C. In the frame of this research, the structure of two workshops was directly measured and surveyed, and along with it, there were also the construction documents consulted. The formulas for heat balance calculation were set up from theories of energy balance and real construction of the building. The reduction of roof windows' area or improvement of the shape of the windows would influence the heat losses of the building. There can be also the heat exchange and efficiency of the heating equipment improved. The obtained results are the basis for proposal of a suitable building design, choosing and using of heating systems to achieve reasonable and economical conditions. The difference between workshops shows the influence of the structure of the workshop on the heat balance. As a general conclusion, it must be said that the roof windows' areas have a big influence on the heat transmission and they are the main factor responsible for heat losses and heat gains in the buildings. The formula could be useful for the designer of the building, which saves time, cost, energy and resources to keep indoor thermal comfort for the workers' performance.Keywords: calculation, heat transfer, temperature, workshop. IntroductionBy understanding the building's thermal loads and its intended using, we can more effectively use energy from the sun to save energy from the passive heat system [1]. We can even generate energy onsite using resources that would otherwise be thermal loads that would demand energy. High performance buildings seek to reduce these loads as much as possible [2; 3].The thermal load includes external thermal loads and internal thermal loads. External thermal loads come from heat transfer through the building envelope from the sun, weather, and the outside environment [4; 5]. The building envelope includes roofs, floors, walls, windows, and any other surfaces that separate the inside and outside of the building. The building envelopes interact with external thermal load to product external gains or losses for the building.The internal thermal loads come from heat generated by people, lighting, and equipment. In winter, the internal gains by people and lighting are not enough to keep warm inside the building [6]. Therefore, designers have to calculate, how much heat energy to use for warming up and then they will choose suitable heat equipment to achieve reasonable and economical conditions.In summer, the external heat that enters through the building is very high. The common ways are solar radiation and indirect solar gains that warm up exterior building surfaces [7].In winter, mainly ...