Energy Efficiency
Climate Change

The case for waste-heat-recovery

Alessandro Bracco
December 19, 2019

Fifty percent of the energy consumed by production processes is being wasted

More than 32% of the total US energy consumption is consumed by the industrial sector. For the European Union the equivalent number is 25%. It should be no surprise that a lot of energy is consumed in the processing and production of goods. What might come as a surprise, however, is the amount of energy wasted in these processes. A report from the U.S. Department of Energy shows that more than 50% of the energy consumed by production processes is wasted. Most of this energy waste is in the form of heat. Not only is the heat a waste of energy but companies also often have to resort to expensive, energy-consuming cooling systems to get rid of this excess heat.

Waste-heat-recovery systems make use of heat that is created but not needed in the production process. The idea is to send the heat to where it is needed like district heating, power generation or even other businesses – helping them cool their production and cover their heating needs.

Waste-heat recovery could become essential to a more efficient future, wasting less energy and using all the heat generated for production, and. benefiting people in the process. Heat is a natural result of the production process, we should make it work for us.

How waste-heat recovery has affected the world so far

There are a few pioneering examples of waste-heat-recovery systems in Europe. These cases use heat generated from production or other activities to heat both residential and commercial buildings and showcase the many benefits of waste-heat-recovery as well as the variety of possible applications.

Heineken’s brewery in Austria aids residential consumers

Beginning in early 2018, Heineken’s brewery in Puntigam, Austria, formulated a plan to give back to the community it brews in. The waste-heat from the fermentation process now provides heat and hot water to around 800 residential dwellings that house around 2,000 people. Once the water has been used, it is channelled back into the brewery to be used again.

This sustainable system also saves the brewery more than 10% on their regular cooling bill. This process is revolutionary and according to Heineken, the first of its kind. The brewery is paving the way when it comes to creating a new method of heating and giving back to the community that supports the company.

ROCKWOOL Group’s Danish factory in Vamdrup helps heat homes

Last year,1,500 local homes were heated thanks to the waste-heat recovery system at ROCKWOOL Group’s factory in Vamdrup. The heat is generated by the ovens used in the stone wool production and the waste-heat-recovery system has been integrated to cool the cooling water. Because of this system, homeowners save more than 10% of their heating bills each year and the factory has a reduced need for expensive cooling towers.

A similar program is implemented at ROCKWOOL’s Doense factory, also in Denmark.

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The London Tube heats homes in winter

Around one-third of the United Kingdom’s carbon emissions come from heating alone, so the United Kingdom has crafted a plan to warm homes using waste-heat. One of those projects involves the London Tube. The plan is for the heat to flow underground, through the tube, (hmm, this one could use a bit more explanation…) to the homes of civilians and residents. It’s a more efficient system than the typical district energy plans, and it allows for less carbon to flow into the atmosphere as well as supports the civilians who need heat most.

Amazon’s deal with Westin

In recent years, commercial buildings have also utilised the heat from other facilities’ processes. Amazon’s headquarters in Seattle, Washington, has made a deal with Westin to buy their heat waste. Westin Building Exchange, a ‘carrier hotel’ that houses server hardware for more than 250 telecom and internet companies, is located just across the street where the hardware is producing large amounts of heat. Westin used to simply release this heat into the air but now it is used to heat Amazon’s offices and the building.

This example shows how waste-heat-recovery is not only limited to heat from production in heavy industries but also a way to mitigate heat waste from almost any heat source.

The benefits of waste-heat-recovery

When manufacturers deploy waste-heat-recovery systems they benefit both the manufacturers, the receivers and the environment.

The heat supplier will, in most cases, also benefit from reduced cooling costs. Channelling cooling water into local district heating cools the water in the process and reduces the need for expensive cooling systems. Those receiving the heat also have lower costs.

The main beneficiary is the environment, however. The heat generated in production processes exists whether we to make use of it or not. When heating is supplied through a waste-heat-recovery system, it means that less energy is required overall. This leads to higher energy efficiency, lower CO2 emissions, and less heat released into the atmosphere as waste.

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