3.2. Selection of circulating pumps

Circulation pumps are provided for heat supply from boilers or local water heaters and are installed in the boiler room or heat point. Pumps are selected according to two parameters: flow, kg / h, and design pressure, kPa.

Supply corresponds to the coolant flow rate for the heating of the served building or group of buildings. In the course project, we can assume that the boiler or heat point (TP) serves one calculated building, and the pump flow corresponds to the water flow in the first section, going from the water heater to the building. The pressure of the pump Dpnas is made according to the recommendations in subsection. 2.3.

The brand of the pump is selected on the flow and pressure. In the central heat points serving individual neighborhoods, pumps of type K can be installed (Table 3.3).

Table 3.3

Characteristics of K-type pumps

Fig. 3.5. Consolidated graph of the fields Q - H circulation pumps type UPS

Currently, many companies produce compact circulation pumps that are installed without foundations directly on the circulation pipe. Characteristics of pumps brand UPS, manufactured by Grundfos, are shown in Fig. 3.5.

When placing the pumps in the basement of the building, they are installed under the staircase (to avoid noise) and attached to the pipelines through flexible inserts.

		The system should have two pumps (working and standby), a bypass line is arranged around the pumps to maintain circulation due to natural pressure during accidents. The installation of pumps is shown in Fig. 3.6.
Fig. 3.6. Scheme (in plan) of the installation of circulation pumps: 1 - return line; 2 - to the heat exchanger or boiler; 3 - pumps