Thermal circuit is composed of a cogeneration unit Vitotwin 300-W, of a manifold vertical combi cylinder bank for DHW heating Vitocell 340-M (750 liters), and the central heating system (CHS) which is connected to it. Accumulation cylinder bank also serves as a storage heat exchanger of non-potable process water (TV). Mixing valves for heating and process water serve to maintain the required temperature and to increase the efficiency of thermal energy.
Cogeneration unit achieves a heat output of up to 26 kWt and electrical power of 1 kWe. Cogeneration unit operation will depend on the projected demands of heat for DHW and central heating. Detailed descriptions of specifying parameters, that trigger the cogeneration units operation, are listed in the attached documents.
Temperature and a flow of heating water from the cogeneration unit characterize its thermal flow. The thermal flow is led into the cylinder bank, which, together with the regulation, allows the Stirling engine to run for an extended time and to maximize the overall electricity requirement. The accumulation cylinder bank is connected to the central heating system with the expected temperature gradient about 55° C/40° C. As a part of simulation, it is possible to adjust for the mixing of heating water from the central heating system to a desired temperature, or turn it off. The temperature of supplied heat into the heating system is measured. The heating water transfers warmth to the process water in the accumulation bank. As a part of the simulation, it is possible to adjust the mixing of warm process water to a specific temperature, or turn it off. The amount of heat needed to heat TV is also measured.
Thermal circuit diagram of a cogeneration unit made in program Matlab Simulink is included in the Annexes. Length simulation is set to 86400s, which corresponds to 1 day. The simulation is performed in following operations:
1) Winter mode: DHW - on, heating system - on
2) Summer mode: DHW - on, heating system - off
Acknowledgement:
The database contains the results of research work funded by project of specific research FEKT-S-11-19 and was to created in Center for Research and Utilization of Renewable Energy Sources. Author gratefully acknowledge financial support from European Regional Development Fund under project No. CZ.1.05/2.1.00/01.0014.
