Distribution of heat BALKAN ENERGY started with intense planning and preparation of projects for domestic hot water (DHW) systems, which are connected and use the heat energy from the district heating system.
The DHW systems, described below, can be used in buildings with horizontal internal heating installation and with individual heat meters, and the systems must be constructed according to a previously prepared project for heating and domestic hot water (from licensed companies)
Installation of DHW systems, without a project is not allowed, due to a risk of impairment of the heating quality.
- Combined DHW boilers
In order to further utilize the heat distribution system and save electricity for DHW water heater to heat for baths and kitchens facilities, designers of the internal heating installation are encouraged to include combined water heaters in their projects and investors of new buildings to incorporate them.
This way of DHW heating, beside the money savings, ensures constant DHW supply, heated through the district heating system (06-22h), which increases the comfort of the customers.
The combined DHW water heater uses two heating sources – heat exchanger (usually in a form of spiral pipe) connected to the heating installation and electric heater which during the heating season is used for additional heating of the DHW.
The combined water heater must include automatic regulation, i.e. integrated control system, in order to achieve maximum use of the heat energy from the heating distribution system, as well as to prevent outflow of the hot water back into the heating distribution system (when the water is heated by the electric heater). The control system must include electro-motor open/close valve for the circuit of the heating installation, controller with display for temperatures and commands, and temperature sensors.
In 2015 DHBE installed 3 combined DHW water heater in its administrative building, to meet the needs for domestic hot water of the employees, in order to explore and evaluate the electrical energy savings during the heating season in practice. The conclusion is that during 5 mounts around 70% of the energy needed for DHW heating was obtained from the district heating system.
The detailed recommendations of the combined DHW water heater characteristics are given in the Special technical requirements for design, construction and maintenance of the distribution system.
- Solar collectors
The use of solar collectors for DHW supply is another way of achieving energy and money savings, and their usage is recommended. The combination of solar collectors with the heat distribution system and electrical energy as an additional source, significantly improves the profitability of the investment, compared to the DHW systems just with solar collectors and electrical energy. The system must be designed with a maximum usage of the solar energy, as a primary source, and the heat energy from the district heating system to be used as a secondary heat source. The electrical heater is used as additional heat source, if needed (at night and for increased demand during the non-heating season). The solar system will be used as a pre-heating of the cold water, and the other sources will be used for additional heating. The system will be controlled with a help of automatics, in order to achieve maximum synchronization and accuracy.
The principled scheme of the system is given below:
The detailed recommendations of the system characteristics are given in the Special technical requirements for design, construction and maintenance of the distribution system.