By Jane Marsh
As the demand for sustainability in everyday living grows, there’s a pressing need to explore innovative ways to utilize wasted energy for home heating and cooling.
One approach is to harness heat waste from industrial facilities and data centers and convert it into useful thermal energy. This process can go a long way in significantly reducing the residential carbon footprint.
Waste heat is a byproduct of various daily processes that use energy. For example, a running car engine generates heat, which dissipates into the atmosphere.
Power plants, manufacturing facilities and data centers create massive amounts of waste heat. According to the United States Environmental Protection Agency, 64% of the energy used for electricity generation is wasted through expelled heat. Making up for the lost power often requires combusting more fuels, resulting in higher production costs and carbon emissions.
Waste heat in data centers is growing rapidly as the demand for global internet connectivity increases. Microsoft estimates 1 megawatt of electricity consumed per hour in a modern data center produces one MWh of heat energy.
Harnessing Heat Waste for Energy
Waste heat recovery systems have different processes but share a similar goal — to utilize otherwise wasted energy and convert it into electricity for improved sustainability. Examples include:
This device transforms heat differential into electrical energy. Picture two strips of metal, one steeped in icy water and the other in boiling water. The variance in temperature creates an electric current, which the TEG converts into power. This is known as the Seebeck Effect.
Strategically placed TEGs in power plants and data centers capture heat at designated discharge points and convert it into electricity for residential use. Recent tests by the California Energy Commission showed a TEG device can generate roughly 500 watts of electricity, which can power small devices such as laptops, mobile phones and coffee makers. Multiple larger generators can power HVAC systems and other household appliances.
HRV devices capture heat from the stale air blowing outward and use it to preheat the incoming fresh air in the house. The system can also function in reverse, removing heat from the incoming air and transferring it to the outgoing air.
This process mitigates indoor energy loss, which means homeowners can spend less on heating and cooling their homes more sustainably.
Water heaters make up 14%-18% of a household’s utility bill. Boiler economizers can help lower these costs by recovering heat lost during water heating and using it to preheat the feedwater. This means the boiler does not have to expend as much energy heating the water, lowering consumption. According to the U.S. Department of Energy, a boiler economizer can reduce fuel requirements by up to 10% and pay for itself in less than two years.
Using an economizer can also extend the life of the boiler. Thermal stress from the cyclical heating and cooling of the fittings can increase wear and tear over time. Preheating the feedwater reduces the temperature differential impact, giving it a longer service life.
This technology produces heat and electricity from the same fuel source. It essentially increases the amount of energy harnessed from fuel combustion processes. Most residential CHP systems burn mains or liquified petroleum gas to generate electricity. This process produces heat, which the device captures to provide heating and cooling at home.
The EPA estimates over 4,700 CHP applications, including residential, commercial and municipal buildings across the U.S.
Data centers are fast becoming a mainstay source of reusable energy. Roughly 97% of the heat generated by servers, cooling systems, and network devices can be repurposed for home and office use.
Governments use these technologies worldwide to reuse data centers’ waste heat to power residential areas. In 2023, the U.K. government committed £65 million to green projects providing heating and hot water to over 10,000 homes.
In Dublin, Ireland, recycled heat waste from Amazon’s data center provides low-carbon heat to homes, commercial spaces and government buildings. The project is expected to save 1,500 metric tons of carbon yearly, helping the country meet its 2030 renewable energy targets.
Meta’s facility in Odense, Denmark, also features a heat waste recovery system designed to capture 100,000 MWh and supply it for home heating. This process utilizes district heating, meaning one heating system delivers energy to thousands of homes, improving collective efficiency and lowering individual household heating costs.
Environmental Benefits of Utilizing Heat Waste
Preventing thermal energy from dissipating into the atmosphere is highly beneficial to the environment. These include:
- Energy efficiency: Less heat wasted means lower overall energy consumption, reducing the reliance on traditional fossil fuel power sources. This helps minimize greenhouse gas emissions.
- Lower carbon footprint: Recovering and reusing wasted heat reduces the strain on the atmosphere, contributing to a greener and more eco-friendly future.
- Renewable energy: Heat recycling devices supplement the environmental benefits of clean energy when connected to a sustainable source like solar or wind.
- Energy security: Utilizing waste heat locally contributes to energy security and reduces the dependence on ecologically unfriendly energy imports like coal and crude oil.
- Resource conservation: Heat recycling systems transform waste into energy. This process aligns with the sustainability principle of reusing existing resources as long as possible.
Making the most of heat generated from everyday applications is environmentally and economically promising. However, some roadblocks impede global adoption.
Industrial facilities and data centers are located far from residential areas. Supplying customers across such long distances will require infrastructure that might impact the ecosystem across the area covered.
Cost is another issue. Installing heat reuse systems across an entire city requires heavy capital investment. The upfront expenses alone would be astronomical. After installing the devices, there must also be a budget for training homeowners on proper usage and maintenance requirements.
Nevertheless, the industry’s future looks green, with the waste heat recovery market projected to reach over $127 billion by 2030.
Recycling heat waste provides a practical solution amid growing environmental concerns and rising energy costs. As countries prioritize eco-consciousness, integrating heat reuse systems will be pivotal in transitioning to a more sustainable future.