Significant reductions in heat losses and pump electricity usage

Improved performance of dwellings

Successful reduction in carbon

Background

The project focused on a residential development consisting of multiple blocks with a total of 791 dwellings. The development utilised a heat network for heating and hot water provision. The heat network comprised a combined heat and power unit along with four non-condensing boilers, which supplied domestic hot water and space heating through a two-pipe system featuring underfloor heating.

Challenge

The project faced two primary challenges affecting the heat network’s performance. These challenges included significant heat loss due to uninsulated terminal run pipework and elevated operating temperatures. Additionally, high electricity usage for pumps increased the overall cost of heat delivery to residents.

FairHeat Solution

To address the issues, FairHeat’s project team considered various potential solutions, including insulating pipework, lowering flow and return temperatures, adjusting pump control, and removing unnecessary pumps to minimize energy consumption. The team proposed three distinct work packages aimed at improving the heat network’s performance:

  • Work Package 1:
    o Recommissioning heat interface units and underfloor heating
    o Insulating terminal run pipework
    o Adjusting network bypass valves and pump controls appropriately
    o Enabling automatic rotation of all plant room equipment

 

  • Work Package 2a:
    o Installing substation control valves
    o Reducing flow temperatures
    o Installing minimum flow rate protection at pumps
    o Closing riser bypass valves
    o Removing unnecessary equipment

 

  • Work Package 2b:
    o Replumbing a section of the primary heat network
    o Further reducing flow temperatures
    o Installing substation control valves
    o Installing minimum flow rate protection at pumps
    o Closing riser bypass valves
    o Removing unnecessary equipment

Results

The approved works for enhancing the heat network’s performance in the residential development encompassed several activities. These included recommissioning residential heat interface units and heating systems, insulating terminal run pipework, closing and removing riser bypasses, adjusting pump control logic, installing valves to regulate temperatures across plate heat exchangers, reducing network flow temperatures, re-piping plant room pipework and equipment, and installing additional water quality equipment. These measures were selected to maximize performance while minimising costs.

The expected outcomes of the implemented works include increased efficiency by reducing operating temperatures, heat losses, and pump electricity usage. Moreover, the improvements are anticipated to enhance the system’s reliability and lifespan while reducing the carbon intensity of heat in the residential development. The project aims to mitigate the impact of rising gas and electricity prices on the cost of delivering heat and hot water to the dwellings.

The project is currently in progress, with most of the plant room works already completed. Only the final control changes remain. The re-commissioning efforts in the serviced apartments have already demonstrated significant reductions in heat losses and pump electricity usage across the heat network. The analysis of graphs indicates notable improvements in flow rate and operating temperatures. Following the servicing activities, average return temperatures decreased by approximately 25°C (from 75°C to 50°C), while flow rates were reduced from 1.4 m3/h to approximately 0 m3/h, indicating the removal of bypasses from the system.

The project’s interventions in serviced apartments resulted in significant reductions in heat losses and pump electricity usage throughout the heat network.

The majority of dwellings have already undergone servicing, and their improved performance has been confirmed through analysis from Guru Pinpoint reviews. The most common issue addressed was the removal of bypasses in the heat interface units (HIUs).

The project successfully reduced the carbon intensity of heat in the residential development while minimizing the impact of escalating gas and electricity prices on heat and hot water costs for the dwellings.

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