Thermal storage heaters: Performance test (NT VVS 099)

  • Report #: NT VVS 099
  • Approved: May 1993
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  Thermal storage heaters are designed to enable electrical energy to be supplied and stored as heat during the night. The stored heat can be used during the day when energy prices are normally higher. The purpose of this test method is to determine and present the main performance characteristics of such thermal storage heaters. The purpose of the test method is also to determine the temperatures on exposed surfaces and at the air outlet of the heater, as well as the sound power level from the heater. The automatic control system of the heater and the effects on thermal comfort are not treated in this report. In addition to the results from the test, the test report also contains a functional description of the test object. The main field of application is conventional thermal storage heaters which accumulate energy in a material of high thermal capacity. The heaters are supplied with energy during the night and accumulate the heat in an accumulating core which reaches high temperatures. The common temperature level is 300-600 °C. The heat is discharged during daytime. The heat discharge is achieved by means of the indoor air which is conveyed through air ducts inside the accumulating core. The heat discharge can be controlled in different ways. There are heaters with forced convection, where part of the heat discharge is controlled by a fan. Other heaters have natural convection, where part of the heat discharge is controlled by dampers or similar devices. There are also heaters with combinations of fans and dampers, where the dampers are adjusted in different positions to obtain a mixture of indoor air and heated air. This test method can also be applied to other types of thermal storage heaters, which for example distribute their heat by using water as a thermal transfer medium.