To help create a low energy building for the Humanities Faculty at The University of Manchester Oventrop’s Aquastrom T Plus domestic hot water return valves have been used on three independent distribution systems in the new building. Additionally, as well as general and commissioning valves, 350 TRV/lockshield combinations were supplied. Oventrop equipment was chosen by DSSR, Manchester, consulting engineers for the project, the TRVs on the basis of past experience and the Aquastrom T Plus for its compactness and functionality.

Mechanical services contractor for the new £20 million, 5-storey building was N G Bailey. 10,000 square metres net of accommodation has been provided for the Schools of Social Sciences and Environmental Sciences. Natural ventilation predominates, with comfort heating/cooling in internal areas as required. Laboratories occupy ten per cent of the building.

Facing east to west, the building houses over 350 offices for teaching and post graduate staff and uses steam as the primary source of heat. In the ground floor plantroom this is converted to LPHW using plate heat exchangers to serve three heating circuits. Two variable temperature circuits serve the building, one serves the east and one the west. Each floor can be isolated. Main entrance areas have underfloor heating. A constant temperature circuit serves air handling units and hot and cold water services via calorifiers located in three roof top plant rooms. Oventrop valves are used throughout.

Below each window in the office and teaching areas is a radiator complete with an Oventrop AV6 TRV/lockshield valve combination. There are over 350 in all and the circuits operate with variable speed pumps which measure differential pressure within a reverse return system.

Aquastrom T Plus is a multifunction domestic hot water (DHW) secondary circulation regulating valve which, as well as simplifying the commissioning stage, provides significant energy savings by thermostatically controlling temperature and flow in the systems. The standard valve incorporates features that are only available as options and/or additional products from other manufacturers.

The valve is factory preset and operates as a temperature control valve on the DHW return. Once the system is up to temperature the valve throttles down to a residual minimum flow to limit the amount of heat loss in the system and reduce the energy/cost required to raise the return water back up to flow temperature. As soon as the hot water in the return pipe cools to the preset temperature, usually 57ºC, the valve responds by allowing more flow thus eliminating cold dead legs and the risk of Legionella bacteria growth.

As well as temperature balancing, Aquastrom T Plus also provides a hydronic balance of the DHW system and enables automatic system pasteurisation when the HWS generator or stored water temperature is raised above 70ºC. The valve always provides a residual flow rate to maintain continuous circulation. A manual isolation facility is provided for maintenance purposes.

Email: keith.tearle@btconnect.com