Case Study

Development of a new secondary heat recovery unit

The Challenge
A leading European manufacturer of oil fired boilers required a new condensing heat recovery unit in order to offer increased energy efficiency in anticipation of enhanced European Fuel Efficiency Regulations for new boiler installations. The customer specified that the new unit must to be able to take in exhaust gas temperatures of up to 300°C and vent at about 80°C. It needed to work with their existing oil fired boiler design and, as these boilers are designed to be installed in a domestic application, it had to be very compact.

The Solution
CSi Italy have a long history of working in the heating industry and possess extensive skills and knowledge in developing heat exchanger solutions. CSi Ltd developed a new heat recovery unit, designed and tuned to match the specific back pressure and efficiency requirements of the client's particular oil fuelled boilers rated from 18 to 24kW. The new unit efficiently takes the hot boiler exhaust gases, which can be up to 300°C, and vents to the atmosphere at about 80°C. The recovered heat can then be used to preheat water as it enters the heating system.

CSi Ltd based this design around a patented high efficiency stainless steel tube, which is designed for products required to recover heat when operating in a very hot and corrosive atmosphere. Type 904L stainless steel was chosen for this application due to its ability to withstand the corrosive effects of Sulphur Dioxide (SO₂). Within the new heat recovery unit, this corrosive Sulphur Dioxide is collected in a condensate management system for safe neutralisation and disposal.

The unit was designed to retrofit to existing boiler installations, giving the company’s customers the opportunity to combat the ever increasing price rises of domestic fuel oil.

Summary
The CSi development team worked very closely with the customer throughout the development process, supplying beta test models which were successfully tuned for optimum efficiency. Although the customer had its own dedicated R&D team, the specialist knowledge of CSi was invaluable in bringing the new condensing heat recovery unit to market in time to meet the launch date set by their marketing team. The client are now able to offer increased energy efficiency in anticipation of enhanced European Fuel Efficiency Regulations for new boiler installations.