Pressure sensors upgrades performance of district heating network
Customer Type: District Heating operator
Industry: Industrial
Application: District Heating Network
Solution: Druck's UNIK5000 Pressure Sensing platform
The Druck team was approached by its Channel Partner for a District Heating operator, based in Hungary, who needed assistance with building a new decentralised heating network.
District Heating (DH), is a system for distributing heat and hot water to residential and commercial properties via heating networks.
District Heating Systems are a closed loop network of insulated pipes laid around a city which are used to supply hot water to customers. The heated water is transferred from a central hub which uses gas or biomass fuel to heat the water before it enters the supply pipe network. The heated water enters the buildings from the supply pipework and heat is then transferred to the building’s pipework via heat exchangers. The cooled water is returned to the central hub via a network of return pipes which run in parallel to the supply pipes. Previously, Druck’s customer would perform all necessary district heating pressure and temperature measurements, as well as control/monitoring operations at one central hub. This meant that the pressure and temperature of the hot water supplied were consistent, regardless of the distance involved between the central hub and the location of the building requiring heating and hot water. Druck’s customer decided to decentralise their activity and implement several small local heating centres. By creating these substations, they felt they would be able to serve their customers more effectively by saving energy and cost.
With a centralised system, faults were recognised immediately in the central hub, facilitating the rectification of the fault. Therefore it was essential that the new local decentralised heating centres were equipped with identical control/monitoring systems.
Druck’s customer invited tenders to establish the network of 700 local decentralised heating centres, which included the supply of pressure sensing equipment. Due to the nature of this task, system integrators were engaged to oversee the technical aspects of the contract and installation. Druck’s channel partner (who were bidding for the aspect of the contract concerning pressure sensor supply) felt Druck sensors would be ideal for this application. However, the winning bidder for the entire tender is a system integrator who also produce pressure sensors in another division of their business and naturally wished to specify their own pressure sensors for this application.
The installation of the system integrator’s heating system containing their own pressure sensors went ahead and during operation a number of the pressure sensors failed. At this point the system integrator replaced their own sensors with low cost pressure sensors produced in a developing economy – which also failed during operation.
Faced with these reliability issues and the uncertainty that impacted their operations, the end customer decided to contact Druck directly. Having conducted a technical review of the application requirements and considered the suitability of Druck’s UNIK5000 pressure sensors for this application, the end customer opened a second tender for 900 units.
In light of the earlier problems with pressure sensor reliability, the end customer proposed re-fitting the equipment themselves and selected Druck as the supplier of 900 UNIK5000 pressure sensors.
Knowledge of Druck’s product range allowed the channel partner to recognise that the UNIK5000 would give the customer a more accurate and reliable solution which provides significant operation cost savings.
In the district heating system, as seen on picture 2, the input and output connections of the hot water pipeline led from the central hub. This is the primary loop containing water of approximately 90-100°C and a pressure of 16 bar. The system includes a hydraulic network, a processing system and a telemetric system supplying the pressure and temperature data which is monitored locally.
Druck’s UNIK5000 configurable modular pressure sensors were selected to monitor the pressure in the secondary loop leading into the building for heating and consumer water heating purposes. One pressure sensor is needed in every local heating centre. Within the heating system of a building, a pressure equalising reservoir is located at the top of the heating pipe system. Changes in the water level within this reservoir are monitored by the pressure sensor located at the lowest point of the system.
The introduction of Druck’s UNIK5000 provided the following benefits:
The elastic silicon pressure sensor in the Druck sensors is well suited to multiple pressure cycling with no degradation in performance over time or at extended periods at elevated temperatures.
The high quality machined and welded module is totally robust in such an application and the UNIK5000 uses high quality electronic components capable of operating for many years at elevated temperatures.
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