Almost all large industries sectors have a huge potential of surplus heat that could be used as industrial heat source in several district energy applications.
On the same way that larger heating demand is requested by industry for heating process it seems that waste heat from exhaust air, cooling tower or medium temperature heat from steam condensate are available close to the heating and cooling networks.
When a waste heat mapping is developed in a large city as per municipality plan all stakeholders could obtain clear benefits from an economic vision creating a circular economy.
Industrial surplus heat: A low cost heat source
In an industrial area, different cooling and heating processes are in constant operation creating a large range of heat source available at very low cost for utility providers.
District energy market need to focus on these large energy source potential to create a value chain that will improve their efficiency at the same time that will reduce their dependency from low temperature heat sources.
If we take in consideration that all industrial cooling system employ heat dissipation systems that required large water and electricity consumption (cooling tower or air cooled condenser) it will be more sustainable create a connection to the District Energy networks to reuse this low grade heat as a industrial heat source for a heat pump.
The larger CO2 emissions are coming from the industry and large energy demand too.
If industrial processes surplus heat is recovered and reuse for the heating and cooling proposal a new benefit will be created to ensure an economic benefit for the industrial market.
The main benefits for industry and stakeholders will be:
- Improve the efficiency of large-scale heat pump with a high temperature heat source during constant operation period
- Create an added value to the industrial market
- Reduce large water and electricity consumption
- Reduce CO2 emissions
How to integrate a HP in an industry ?
The new challenge for industry will be to decide if heat pump investments will be done inside their own properties to sell the hot water to the district energy market or to create a circular economy selling this low-grade heat source temperature as a low cost energy to the DE market.
In both cases, heat pump integration will be decisive for a clear optimization of the economic modelling of these projects.
Continuous industrial improvement require a complex knowledge about the processes itself but there are different waste heat applications that could simplify the heat pump integration:
- Coil heat exchangers installed in exhaust air from drying process
- Cooling tower by-pass to heat pump evaporator
- Plate heat exchanger on return of steam condensate
Definitively all the waste heat recovery will be a cost effective solution from both sides (producer/consumer) with an interesting payback.
In the meantime, the technical question will be how to adapt the heat recovery with the heating demand? Thermal energy storage will be the right answer to well balance the energy required.
A large pit storage used as seasonal storage would be enough to create a flexible system to increase industrial heat recovery from different industrial plants and satisfy the utility provider network as a low cost and reliable heat source.