Refrigeration systems place demanding requirements on the piping system. Not only is the primary piping system critical to the efficient, reliable operation of the refrigeration plant, but the secondary refrigerant fluid system also plays a critical role in optimizing running costs, energy efficiency and keeping maintenance to an absolute minimum. Choosing the correct material for both piping systems is important for optimizing plant costs and performance.
Often the same piping material is used for the secondary system as for the primary system. In breweries, wineries, cold storage facilities and other below-freezing applications, this means that copper or steel typically is used for the whole system. This can be an expensive option if there are long runs of pipe involved.
However, the only alternatives for secondary piping have been copper, steel or stainless steel, all of which have potential drawbacks. Some plants have even used polyvinyl chloride (PVC), which has a low-temperature limit of 0°C. At this temperature it becomes brittle – highly unsuitable for glycol (anti-freeze) solutions, which have a temperature of -8 to -2°C.
Anyone who works with steel, copper or PVC piping is familiar with the problems experienced at below-freezing temperatures. The insulation used on these pipes often absorbs water from the atmosphere, which negatively affects the insulation and reduces the system efficiency by increasing operating costs. Water absorption also can cause ice build-up, which will crack PVC pipes and cause corrosion on metal pipes. These problems lead to excessive maintenance and downtime.
Within the last 15 years, ABS (acrylonitrile butadiene styrene) piping materials have been developed that provide a durable, long-lasting alternative in these applications. Retrofitting traditional pipework to ABS piping can provide a savings in maintenance and operations costs.
ABS is a thermoplastic material that performs well in temperatures from -40 to 60°C with less condensation and ice build-up compared to other piping materials. Piping made from ABS does not corrode and is crack resistant, which reduces maintenance to a minimum. ABS piping typically lasts 25 years or more with virtually no maintenance requirements. The piping also has a roughness factor of 0.007, which is six times smoother than steel. The smoothness of the plastic pipes prohibits a build-up of deposits from the fluid, thereby preventing the reduction of flow in the pipe. Unrestricted flow also optimizes the efficiency of the system in terms of reduced pressure loss, a performance characteristic that remains constant over the life of the pipe.
Cost is an important factor when considering any upgrade or retrofit. Material costs, the labour required to install the pipe and the amount of downtime required to complete the retrofit all are part of the upfront costs associated with the project. However, these costs can be recouped relatively quickly with ABS piping due to the reduced downtime, replacement and repair requirements.
ABS piping is fitted together with solvent cement (similar to the joining technique used for PVC piping), which merges the materials together to form one homogenous material. This means there is no hot welding on site. ABS piping also must be insulated like any other piping for use in glycol or brine cooling systems. Fortunately, pre-insulated pipes and fittings can be specified, and these options can minimize installation time.
In breweries, wineries, cold storage facilities and other applications using glycol or brine cooling systems, secondary piping can be a key factor in determining an operation’s efficiency and profitability. Retrofitting a steel, copper or PVC system to ABS piping can reduce maintenance costs and downtime while also increasing the overall efficiency of the cooling system.