There will be instances when constructing an annex or an extension affects the original building. Apart from structural concerns, the HVAC pipes can also be damaged, especially if the boiler room or air-conditioning unit remains in the main structure.
When this happens, there are only two solutions: have a separate HVAC unit for the extension or extend the HVAC and pipes from the main to the annex. The former allows for an easier design yet higher maintenance and operational costs, while the latter requires extension pipes and other equipment to integrate both systems.
Expanding Pipes and Utilities
Masterflow Solutions and other experts suggest using a pressure vessel to handle the extra load. In most cases, it’s less costly to extend the pipes from the boilers and air-conditioning units than to buy a whole set for the new structure. This is where issues crop up during implementation, especially if the air-conditioning unit is underpowered to service a larger volume.
For variable conditions, having a single unit mean that it would be cycling faster and restarting several times per hour. There are units that have six start limits and would require frequent maintenance once the limits are reached. When you consider the operational requirements, having an additional buffer tank also puts less strain on the chilled water system.
Buffer tanks store chilled water to allow continuous operations in case of a power outage. In addition, they also comply with Australian Standard AS1210 regulations for pressure vessels.
Although AS1210 was designed for mine use, the durability and tank strength required means that these exceed the requirements for chilled water buffer tank storage for data centres and other buildings. Constant temperatures are assured, even in the event of a power failure or due to a delay for the power generator to kick in.
The use of a buffer tank and additional piping is a simple and elegant solution to building extensions. One thing to remember: The builders have to make sure of the compatibility and capacity of the buffer tank with the existing system, and the requirements of the extension building.