BS EN 12977-4:2018 pdf download

BS EN 12977-4:2018 pdf download.Thermal solar systems and components – Custom buil t systems
6.2 Installation of the store
6.2.1 Mounting
The store shall be mounted on the testing stand according to the manufacturer’s instructions. The temperature sensors used for measuring the inlet and outlet temperatures of the fluid used for charging and discharging the storage device, shall be placed as near as possible at least 200 mm to the inlet and outlet connections of the storage device. The installation of the temperature sensors inside the pipes shall be done according to approved methods of measuring temperatures. If there is/are more than one pair of charging and/or discharging inlet or outlet connections, then only one may be connected to the testing stand (at the same time) while the other(s) shall be closed. The pipes between the store and the temperature sensors shall be insulated according to EN 12828.
6.2.2 Connection
The way of connecting the storage device to the testing stand depends on the purpose of the thermal tests which shall be performed. Detailed instructions are given in the clauses where the thermal tests are described. Connections of the store which do not lead to the charge or discharge circuit of the testing stand shall be closed, and not connected heat exchangers shall be filled up with water. All closed connections shall be insulated in the same way as the store. Since fluid in closed heat exchangers expands with increasing temperature, a pressure relief valve shall be mounted. The performance of a solar heating system depends on the individual installation and actual boundary conditions. With regard to the heat losses of the store besides deficits in the thermal insulation, badly designed connections can increase the heat loss capacity rate of the store due to natural convection that occurs internally in the pipe. In order to avoid this effect, the connections of the pipes should be designed in such a way that no natural convection inside the pipe occurs. This can be achieved if the pipe is directly going downwards after leaving the store or by using a heat trap siphon.
6.3.2 Test sequences
6.3.2.1 Introduction
The store is tested on the test stand by different specific test sequences. The sequences are specified to simulate the physical effects, which correspond to the parameter to be determined. A parameter identification program using a store model evaluates the measuring data. Charging and discharging the entire store implies connections of the charge/discharge circuits to the uppermost and lowermost direct ports available at the hot water store. Full discharging is required for conditioning of the store and for the final discharge phase. Full charging is required for all discharge tests, which require that the entire store is charged. The series of the performed tests should comprise two tests, which include stand-by periods. One test is for the entire store, to determine the heat loss capacity rate. The other test concerns only the part of the store, which is heated up (usually the auxiliary heated part). This test is used to determine the degradation of thermal stratification during stand-by. The stand-by period should be such that the losses during this period are approximately half of the stored energy. For these two tests with stand-by periods, the same test should also be performed without a stand-by period.