TT325 BHR and Heat Management Unit HMU
Compressed air production in industrial facilities consumes 10% of your electrical power, on average. While this can vary up or down, it is an industrial average, and is very significant in most plants.
Do you know how much of your power cost goes to producing compressed air? We’ll come back to this in the end of this article.
Up to 95% of the compressor power turns into heat energy. Traditional, older compressor technologies waste most of this energy.
Compressing air heats up the compressed air significantly – in traditional “oil-free” screw compressors, the temperature of the air can reach close to 400°F or even higher and then it has to be cooled. Compressed air is cooled either by air or by liquid. Most smaller compressors (<150hp) are air cooled. Then warm cooling air is ducted typically outside the facility without reusing the energy.
Why not use the hundreds of kilowatts of free energy available?
Cooling air flows for larger compressors are very high because of the low heat coefficient of (cooling) air. This is one of the main reasons why big compressors >150hp and especially >300hp are more commonly liquid cooled. In theory, hundreds of kilowatts of “free” energy is available as heat/thermal energy to industrial facilities. However, this is not the case with “oil-free” screw compressors. Value engineering driven cost minimization has resulted in “one size fits all” products. This makes energy recovery difficult. This energy is often used for heat-based air dryer regeneration which leads into wasting most of the thermal energy.
Tamturbo as a 21st century company does not have the built-in burden of legacy companies with old technologies and reliance on substantial aftermarket business of selling highly lucrative consumable parts and services. Our business model is based purely on the lowest cost of owning and operating the compressors. Tamturbo has put significant effort into designing the most efficient cooling method for our compressors. In addition to capturing the heat of compression, we utilize liquid cooling to protect and recover the heat from the energy-intensive parts of our compressor – the frequency converters, electric motors and the turbo heads. This is built-in as a standard feature which captures up to 93% of the compressor input energy. Please note that this is a real recovery without using somewhat manipulated numbers from using the compressor as a heat pump as it is seen in some marketing materials, promising recovery over 100% of the input energy.
Tamturbo Boost Heat Recovery BHR offers higher temperatures for heat energy recovery
In addition to recovery of significantly higher percentage of input energy, Tamturbo’s patented Boosted Heat Recovery (BHR) offers liquid temperatures up to 194°F for heat energy recovery. This is a much higher temperature than screw compressors can do. The wear of the critical coating on these screw compressors accelerates with higher temperatures. This is why screw compressor operating manuals have warnings about limiting cooling liquid flow to compressor for higher water temperature. Such temperatures and wear have a catastrophic effect on the compression efficiency and, eventually, the need to replace the screw compressor air ends (at very high cost).
Tamturbo technology offers more usable and higher heat load water, with less than 1% impact on the compression efficiency while “oil-free” screw compressors would see efficiency loss of up to 30%.
Easy integration to plant system with Tamturbo Heat Management Unit HMU
Ability to integrate the heat recovery to plant system is sometimes a source of hesitation for utilizing the heat energy from the compressor. Tamturbo Heat Management Unit (HMU) makes the integration easy and affordable. Connections between the compressor and the plant are in one compact module which minimizes the installation work and cost.
Save significant amounts of energy and money by using the heat
Long story short: Lower your total energy consumption by using the heat from the compressor heat recovery. Potential savings add up to 9% of total power cost of your facility. Common uses for the heat recovery energy are: heating the facilities during cold season, preheating boiler make up water, wash down of plant equipment or process lines, pasteurization, process water heating, and others.
Economics are attractive – multiply your existing compressed air power cost by 0.1 and then divide this number by the ratio of your cost of primary energy and electricity. For example (a case from Germany):
Compressed air power cost (electricity) $450,000/year
0,1*$450,000= $45,000/year (the unrecoverable compressed air energy cost), remainder $407,000 (90%) worth is recovered in the heat
$0,06/kWh / $0.14/kWh = 0,43 (ratio of heating energy cost (e.g. natural gas) and electrical energy cost
$407,000 x 0,43 = $175,000 (recovered heat as primary heat energy)
Saving: $175,000 when using Tamturbo compressors to heat up your processes.
In addition to energy savings Tamturbo provides the safest and most reliable compressed air