HOT | COOL NO. 4/2012 - Interface, Users and Utilities

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PULSE HEAT - DISTRICT HEATING FOR LOW ENERGY BUILDINGS

Another experience is that an installation should be considered that connects district heating insertion, heating system and storage tank. This allows plumbing work in the house to be reduced. But this also requires planning, so there is room for a unit with defined measurements in all houses. Pulse valves: A solution has been chosen with a pulse valve on flow to housing group and individual pulse valves on flow to individual houses. Rather than a solution in which there are only pulse valves in each house, this has the advantage that a larger pulse with cold water cannot enter the house by the failure of operation. Rather than a solution with only one pulse valve for the housing group, the system has the advantage that only a little cold water enter the houses at start of the pulse. This is due to the individual valves first opening when the circulation has secured a suitable temperature throughout the flow pipe. In addition the advantage is that the pulse for the individual house can be stopped when the house storage tank is full. Operation: Operation has been selected with cables from the central control boxes, with a combination of control wires and Ethernet cables. There has been some work with the cables, since there have been a few errors in the underground casing pipes, which was part of the development.

The measurements continue, and it is expected that more savings can be obtained by optimizing the system, by better operation of the return temperature and by passing return water into the flow at the end of the pulses. The technique is thus not fully developed, but the results so far can be considered encouraging. Furthermore, the project has resulted in much practical experience from which similar projects can benefit. EXPERIENCE With the project a range of experience in establishing a district heating network with pulse operation has been achieved. Construction: The project includes 22 individual houses being built as dense low-rise buildings. This means that each house has its own developer and own plumbing company. Since the domestic installations are more complex than ordinary district heating connections, there has been some work with the instruction of plumbing companies, and subsequent check of the installations. One experience is that it will be easier to make this kind of special district heating systems in buildings where there is only one developer.

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