Thermal Technology provides cost-effective life extension for air-handling units
The life of air-handling plant at Festival House in Cheltenham has been extended by 10 to 15 years by a complete refurbishment carried out by Thermal Technology for a relatively small investment compared to new units. This multi-storey office block was built in 1989, and its HEVAC plant was 22 years old. CIBSE Guide M indicates a life of 20 years for air-handling units installed indoors, so the plant was due for replacement or refurbishment.
Following a detailed technical survey, a list of refurbishment work was agreed. Much of the work involved treatment of corroded areas on the drain pans, filter frames, coil supports and base frames.
Work carried out by Thermal Technology to improve overall operating efficiency included replacing more with more efficient EFF1 (IE2) motors with efficiencies of 88.7% for 15 kW motors and 89.9% for 22 kW motors. The existing TASC drives were replaced with 3-phase inverters capable of providing the functions necessary for the correction operation of the VAV systems. The fans were deep cleaned, bearings lubricated and new belts and pulleys fitted.
Both AHUs had mixing boxes, but the dampers were stuck in various positions. The dampers were cleaned, drive trains rebuilt and bearings lubricated. The mixing boxes now function as originally designed.
Over the years, heat-transfer surfaces collect dust and dirt, depending on how regularly the filters are replaced. All the heater batteries and cooling coils were cleaned and damage to fins combed out. New panel and bag filters were fitted at the same time.
