Modelling the temperature impact of cold plumes
CERC was commissioned to carry out a novel assessment of the impact of plumes of cold air from an array of Air Source heat Pumps (ASHPs) on the surrounding air temperature.
In work commissioned by Sustainable Energy Ltd, the CERC consultancy team used ADMS 5 and the dense gas dispersion model GASTAR to carry out dispersion modelling of the plumes of cold air. A single elevated jet, representing the emissions from a single ASHP unit, was represented in each model, and plume centreline height and temperature were output.
The ADMS 5 and GASTAR results agreed well; in both cases, temperature reductions decrease quickly with distance downstream. ADMS 5 gives more flexibility in generating and presenting results.
ADMS 5 was used to determine the meteorological conditions giving rise to the largest and smallest reduction in temperature due to the modelled jet. Stable conditions with low wind speeds gave the largest temperature reduction downstream of the release, and neutral conditions with high wind speeds gave the smallest temperature reduction; however, the difference in impact between these conditions was small.
For all meteorological conditions modelled, at receptors of various heights (trees, car park, offices and footpaths), the calculated temperature reduction was in the range 0-2 °C. Below a height of 5 m, the calculated temperature reduction was less than 1 °C.