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

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AUTOMATIC LEAK PROTECTION Automatic Leak Protection takes Leak Surveillance a step further by providing the consumer with an extra security function. In case that the system registers a leakage, the district energy supply will immediately be sealed off in order to prevent water waste and damages. This operation involves no human interaction. The Automatic Leak Protection is a combined solution based on the MULTICAL energy meter’s Leak Surveillance and an automatic valve control system from DanTaet. Leakages in district heating installations stand for some of the biggest challenges and sources of inconvenience. A leakage can occur in places of limited accessibility and cause severe damages before they are detected. Very often a leakage is discovered only by a drop of pressure or at the annual meter reading which will show an unusually high consumption, which means that by then the leakage has also become a considerable economic burden – and then it still remains to discover the exact location of the leak. In Thisted, a community of 15,000 people in northern Denmark, the district heating customers are being offered Automatic Leak Protection. The reason is that the utility (Thisted Varmeforsyning) is upgrading the supply system to a more energy efficient standard which includes a gradual out- phasing of all heat exchangers. Removing heat exchangers has advantages in terms of higher energy efficiency and improved supply control, but it also entails a higher risk in case of leakages, because the former division in a primary district heating system and a secondary system on consumer side will be abandoned in favour of a direct system with no physical separation between the district heating system and the consumer’s heating system. HIGHER SECURITY Obviously leakages in a direct system will to some extent affect the whole district heating system and are therefore liable to cause even more damage at the consumer’s property. In order to take this higher risk into account Thisted District Energy has chosen to offer Automatic Leak Protection as an option to their customers who will actually benefit from an even higher protection against leakages than before. Automatic Leak Protection depends on Leak Surveillance which has already been implemented by a large number of utilities. Leak Surveillance is an option provided by the MULTICAL energy meters that must be mounted with two flow sensors, two temperature sensors and an automatic meter reading system. The two flow sensors are installed in inlet and outlet respectively. Based on a comparison of the water mass the meter calculates a possible imbalance between inlet and outlet. An imbalance will cause an alert which is being sent via

the automatic meter reading system to the central system. An alert will also be prompted if the meter is not idle for a predefined period within 24 hours. Automatic Leak Protection adds further automation to the surveillance by actually shutting the system down instead of just sending an alert. The consumer will experience instant reaction without having to rely on the utility’s crisis preparedness. When the first system was installed in April 2012 in Thisted it immediately shut off the supply to the residence. It was assumed that this first installation was showing a system error, but as a matter of fact, there turned out to be a leakage, and the system was in reality showing its efficiency.

Department Manager, Lars Andersen, from Thisted District Energy demonstrates the automatic leak protection system. The energy meter is connected to the DanTaet control unit automatically operating two check valves. Check valves in the Automatic Leak Protection system shutting off the energy supply when activated by the control unit.

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