Implementation of an Integrated System of Intermittent Heat Supply for Educational Institutions

Abstract

A review of the current world state of application of various heat supply regimes for public buildings is conducted. The efficiency analysis of the use of various renewable energy sources in combined heat supply systems is analyzed. An integrated heat supply system with successive heating of the coolant from low-potential renewable sources of heat (solar system) to high-temperature traditional heat sources (gas and pellet boilers) is developed. A mathematical model of the integrated heat supply system using renewable sources of heat is proposed. This model can be used to simulate the processes of heating rooms in the intermittent heat supply mode. The dynamics of heating of premises with various heating devices: with natural convection (radiator) and forced convection (fan coils) is carried out. During the heating season (2016–2017), the operation modes of integrated systems of alternative intermittent heat supply (ISAIHS) are studied. These studies are extremely relevant for solving the issues of rational use of energy resources. The proposed solutions show that the most effective use of renewable sources of heat can be only in an integrated approach to solving this issue. Also it should be noted the interaction of ISAIHS components: the heat source – the heating system – the characteristics of the building – the operating modes of the premises. As a result of the research, the boundaries of the effective use of various heat generators in ISAHS are established. The influence of the type of heating devices and insulation of internal walls on the effectiveness of ISAIHS operation is revealed. The full-scale tests of a pilot installation of an integrated heat supply system are carried out. The obtained results will help to use heat sources more efficiently with a two-period operation regime for new houses. This can be used to improve the energy efficiency of existing buildings.

Enhancing Efficiency of Using Energy Resources in Heat Supply Systems of Buildings With Variable Operation Mode

“…Thus, the results obtained (Fig. 3, 4) allow to solve an urgent problem -to establish the conditions for the rational functioning of the intermittent heat supply system, taking into account the parameter of the maximum displacement of the heat power of heat generators due to HA: Engineering d ASP =V HA (Q nom -Q min ), m 3 /kW, (8) where V HA -the required volume of the heat accumulator, m 3 ; Q nom -the rated (calculated) thermal power of the source, kW; Q min -the minimum allowable heat source, kW. For example, for the combined heat supply system of the ONPU educational building No.…”

“…In the first case, the variable parameter is the time instant that corresponds to the beginning of the heating mode [6], when there is no reserve of thermal power at low outdoor temperatures [7,8]. In this case, an important factor is the length of the on-time heating period.…”