High temperature heat pumps

  • 08/07/2017
  • Technical Insight

Technology Fast Facts

  • Type of Innovation New to the food industry in Australia
  • Time to commercialise Less than six months (in market)
  • Cost Medium $100,000 to $1 million
  • Complexity Existing in-house

What the technology does?

Industrial heat pumps use a refrigeration cycle to very efficiently transfer heat from the environment to increase the temperature of waste heat streams. With rapid escalation in gas prices and tight gas availability, heat pump technology (driven by electricity) can displace gas by using heat recovered from waste streams. Typical applications recover heat from waste water, hot humid air (e.g. from dryer exhaust), and condenser heat expelled from refrigeration systems, and use the heat for application in blanchers, dryers, and pasteurisers.

How is the technology different?

Heat pumps have been developed in the last decade to be able to deliver heat reliably at temperatures of well over 70°C (and up to generating steam). This has greatly extended the range of applications.

Application & Uses:

A few typical high temperature applications include the following.

  • Drying: Food dryers generally use air heated with steam, gas or hot water. Warm air picks up moisture from the wet product, increasing its humidity, and typically, this humid warm air is exhausted. A heat pump can extract heat from the humid air, which dehumidifies it and the extracted heat is elevated in temperature using the heat pump for elevating the temperature of the now dry exhaust air to heat the dryer.
  • Recovering waste heat from refrigeration system: Waste heat from a refrigeration system has a temperature of 25 - 30°C. With the use of an add-on heat pump, waste heat from the condensing side of the refrigeration system is used to heat water to temperatures up to 80°C. The add-on heat pump further increases the pressure of the refrigerant from the refrigeration system to achieve high condensation temperatures.
  • Pasteurisation: The pasteurisation process requires products to be heated above 70°C, and then cooled. Heat exchange (regeneration) between cold and hot product flows is conducted. Extra heating to bring product to pasteurisation temperature is typically provided by steam, and product cooling after heat exchange is provided by chilled water. A heat pump can extract heat from the product to be cooled and supply this heat at a higher temperature to product to reach pasteurisation temperature.

What the experts say:

High temperature heat pumps are increasingly common around the world (Japan in particular) because of their very high thermal efficiency, and given the current Australian high gas prices and potential supply constraints, this is a technology that should be considered for displacing gas.

Find out more?

http://heatpumpingtechnologies.org/publications/application-of-industrial-heat-pumps-part-2/ http://heatpumpingtechnologies.org/

Disclaimer: This Innovation Insights was prepared by Food Innovation Australia Ltd (ABN 50 164 124 609) (FIAL™). It has been compiled from information and material supplied by third party sources, publicly available information, and expert opinion, which may (in part) be inaccurate or incomplete and which has not been independently verified by FIAL. FIAL makes no representation, warranty or guarantee as to the accuracy, reliability, currency or completeness of the information provided in this Innovation Insights. Use or reliance upon this Innovation Insights is subject to and conditional upon the user not holding FIAL liable in any way for any impact or consequence arising from any of the above factors or the user's reliance on the contents of this Innovation Insights.