Operation & Maintenance of Power Plants
District heating system with intelligent leak protection
An innovative combination of heat meters with leak surveillance and an automatic leak protection system results in higher energy efficiency and optimised customer service. Gert Skriver reports.
T
he fact that District Heating Tisted, which supplies a community of 15.000 people with heat energy, is located on the outskirts of Europe in northern Denmark does not hinder the utility from applying
newest technology and still supply its customers with cheap and stable energy. Te utility follows an ambitious strategy for intelligent energy management with the aim of being energy efficient and keeping costs down. One important parameter with respect to district heating efficiency is to maximize the difference between incoming and return temperature - known as Delta-T - which means that as much energy as possible is being extracted from the water. For the sake of maximising Delta-T, Tisted District Heating recently chose to phase out all heat exchangers and replace them by a direct heating system with leak protection. Heat exchangers in each household offer a way of
regulating the energy consumption and of securing the district heating system by separating the heating system in a primary system on supply side and a secondary system on consumer side. In this way a leakage can be limited to the secondary system.
Heat loss But heat exchangers are not very energy efficient. Te heat exchanger itself causes a heat loss of 5-7°C, and because it is being manually controlled by the consumer it is very common that the thermostat is not set according to guidelines which often causes the heating installation to return too hot water (low Delta-T).
And as just 1°C improvement in Delta-T for the
whole town means a total saving of more than 100,000 Euro, there lies a huge saving potential here. Tisted District Heating therefore decided to dismount all heat exchangers and instead use a direct system which distributes district heating water all the way into the hot-water elements in the homes. An ordinary direct heating system, though, raises a security question because a leakage could affect the whole system. So in order to maintain the same level of leakage
protection, Tisted District Heating introduced the combined Kamstrup-Dantaet solution. Kamstrup flow sensors installed in the inlet pipe and in the outlet pipe register volume and temperature of the water. Te heat meter integrator then translates
volume into mass in order to make a comparison of incoming and returned water independent of temperature. Constantly monitoring the water flow, the meter will register any imbalance between incoming and returned water indicating a
possible leak. Te heat meter will then send a signal to the Dantaet leak protection system which will immediately shut off the installation. Te Dantaet
leak protection consists of a control unit and two check valves which will automatically seal off the installation. Tis not only limits the damage, but also provides an even safer system than before. Once every night the valve in return flow will shut down and cause an increased pressure in the installation. Te higher pressure will reveal any small leakages which could over time aggravate and become detrimental.
Fig. 1. Department Manager Lars Andersen from Thisted District Heating demonstrates the Kamstrup- Dantaet leak protection in a normal district heating installation: flow sensors (black covers) and check valves (red boxes) in forward and return flow are automatically monitored and controlled by the heat meter integrator (grey) and the control unit (blue).
Tis intelligent energy management system heightens energy efficiency, reduces the need for manual work, keeps costs down and even improves home security. Most insurance companies give 25-50 per cent off on premium when the Kamstrup- Dantaet solution is applied. ●
Enter 21 or ✔ at
www.engineerlive.com/ipe
Gert Skriver is Corporate Editor, Kamstrup, Denmark.
www.kamstrup.com
www.engineerlive.com 21
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60