We are currently investigating how thermal stores (buffer vessels) perform from a theoretical viewpoint. The information is presented as two spreadsheets, one being for constant boiler flow temperature and the other for minimum return temperature. The objective is to help engineers to understand the operation of buffer vessels when used with biomass boilers. The study assumes that the thermal stores will be charged at the boiler's maximum temperature and the water drawn from them will be used to blend with the system returns to provide the required flow temperature. This design offers the maximum thermal storage capacity for a given volume.
The thermal stores provide three services if the control systems are suitably designed. The most obvious application is to isolate the biomass boiler from the system load variations. A second use is to provide a place for the heat to go into when the system load is very low. This is important to prevent short cycling of the boiler. The third service is to provide an additional source of heat at times of heavy load when the demand is more than the boiler capacity. It must be stated that not all biomass boiler controls offer this capability. This enables undersized boilers to come for longer periods which means less fossil fuel is burnt. The spreadsheets and some notes on the theory are available from the download page.
Please let us know what you think of the current software. Also, if you would like to see any other developments or modifications please tell us. This software is particularly designed to assist those working in the field of biomass heating systems but most of it is suitable for any heating system. You can use the link at the bottom of the page to send us an e-mail.