Variable speed heat pump compressor for demand side management and network stability

Abstract

Decarbonization of the UK residential heating sector is crucial to meet the Committee on Climate Change recommendations, 2019 of net zero greenhouse gases emissions by 2050. The current progress with residential building sector carbon neutrality is slow and hence acceleration in action is required. The electric vapour compression-based heat pump (HP) system is a mature technology to meet the residential heat load demands but needs performance improvement with better control for end users satisfactions and meeting grid demands. The HP co-efficient of performance (COP) could be improved with variable speed compressor-based system for capacity control due to match between heat supplied and demand by installing additional control devices as a demand side management tool. This also assist in peak clipping and reduces overall energy demand for load shaping. Capacity control with variable speed mode (VSM) performs better than the capacity control with fixed speed mode (FSM) specifically under varying heat load conditions. Hence, this becomes more beneficial in domestic retrofit due to poor insulation characteristics of old housing stock. However little information is available in the literature regarding the retrofit applications of the developed variable speed compressor HP system specifically in UK context.

The contribution to the knowledge from this research work was a) the successful
development of the novel variable speed compressor based domestic Air Source Heat Pump (ASHP) system for seasonal performance improvement, energy savings, that allows flexible network operations due to match between heat supply/and demand by installing additional control devices/heating distribution system, b) Evaluation of the HP that is able to capitalize upon the range of heating capacities that can be generated across the full range of speeds associated with its compressor’s variable speed drive- can respond to heating supply
temperature needs as well as any constraints placed on its operations by electricity costs of electrical network capacity, c) The HP retrofit assessment via annual running cost, and carbon emissions savings in comparison to oil/gas boilers, electric heater and very high heat supply temperature ASHP for UK housing stock using Archetype approach. The HP in VSM annual performance improves by 27% at 35 oC heat supply temperature in comparison to FSM.
Furthermore, the HP(VSM) annual performance degrades by 51% by increasing the supply temperature from 35 oC to 55 oC. The HP annual running cost was higher compared to the advanced GB (90% efficiency) but proved to be advantageous in terms of carbon emissions.

Date of Award	Feb 2022
Original language	English
Sponsors	INTERREG IVA administered by the SEUPB.
Supervisor	Neil Hewitt (Supervisor) & Ming Jun Huang (Supervisor)