What Is Industrial Heat Recovery?
Industrial heat recovery is the practice of capturing heat that a process would otherwise release as exhaust or discharge in cooling water, and putting it back to use elsewhere in the facility. Common sources include dryer exhaust, boiler flue gas, process cooling, and condensate.
Much of this heat is too low in temperature to be reused directly. Dryer exhaust, for example, isn’t hot enough to reheat the dryer on its own. Capturing and upgrading that heat is what allows a facility to put it back to work rather than losing it, which lowers steam costs and reduces exposure to natural gas price swings. This is common in industries with high thermal loads, including chemicals, food and beverage, pulp and paper, and power generation.
How Does Industrial Heat Recovery Work?
A heat recovery project starts by identifying a source of heat that is currently being lost, then choosing a method or technology to capture and reuse it. The right solution depends on the temperature of the source and the desired end use of the recovered heat. A few common technologies are listed below.
- Heat Exchangers: Transfer heat directly from one fluid or gas stream to another without mixing them, for example, moving heat from hot exhaust to incoming combustion air.
- Economizers: A type of heat exchanger that captures heat from flue gas and uses it to preheat boiler feedwater or combustion air, reducing the fuel needed to bring that water or air up to temperature.
- Waste Heat to Power (WHP): Uses recovered heat to generate electricity, typically through a steam or organic Rankine cycle turbine, most common in industries with very high-temperature waste heat, such as cement and steel.
- Steam-Generating Heat Pumps (SGHPs): SGHPs like Arcturus recover low-grade waste heat, then use mechanical compression to upgrade it and generate boiler-quality steam.
Benefits of Industrial Heat Recovery
Industrial heat recovery captures heat that would otherwise be lost and puts it back to productive use. By reusing energy already present within a facility, manufacturers can reduce the amount of new energy required to meet their thermal needs.
Lower Energy Costs
Using less purchased energy translates directly into lower operating costs. At facilities with large thermal loads, even modest reductions in natural gas or electricity consumption can produce meaningful savings over the course of a year.
Reduced Exposure to Energy Price Volatility
Because heat recovery reduces the amount of energy a facility must purchase, a smaller share of its thermal operating costs is exposed to fluctuations in natural gas and electricity prices. Reducing purchased energy can also lower associated emissions and, in some applications, reduce the energy required to reject excess heat through cooling systems.
Improved Energy Efficiency
Heat recovery reduces the amount of purchased energy needed to produce the same useful thermal output. Recovered heat can be reused directly for applications such as preheating, drying, hot water, or process heating, reducing the load on boilers and other primary heating equipment.
Challenges and Limitations of Industrial Heat Recovery
Heat recovery offers a clear opportunity, but capturing and reusing waste heat effectively comes with real constraints. Understanding these barriers helps facilities set realistic expectations for project cost, scope, and impact.
Temperature Mismatch
Waste heat is often available at a lower temperature than the process that could use it. Conventional heat exchange can only transfer heat from a hotter source to a cooler sink, limiting the usefulness of lower-temperature heat.
Matching Heat Supply With Demand
Direct heat recovery requires a suitable use for the heat at the right temperature, capacity, location, and time. These constraints can limit how much of a facility’s waste heat can be recovered and how much of its overall energy demand can be offset.
Cost and Complexity of Integration
Every facility has different heat sources, thermal demands, layouts, and existing equipment. Heat recovery projects therefore often require site-specific piping, controls, and engineering, increasing project cost and complexity.
How Arcturus Expands Industrial Heat Recovery
Arcturus is an industrial high-temperature heat pump that enables recovery and utilization of waste heat. A bypassable heat exchanger captures heat from the facility’s waste heat source and transfers it to a water loop, where heated water is flashed under vacuum to produce low-pressure steam. Arcturus then uses multi-stage mechanical vapor recompression to increase the steam’s temperature and pressure to the conditions required by the facility, using water as the working fluid.
Upgrades Lower-Temperature Heat
Arcturus can recover heat from sources that are too cool for direct reuse and raise it to steam temperatures up to 215°C (420°F). This expands the range of waste heat that can be put back to productive use.
Turns Waste Heat Into a Flexible Energy Source
By upgrading recovered heat into steam, Arcturus connects waste heat to a broadly used facility energy system rather than requiring a dedicated nearby heat sink. This allows recovered energy to serve a larger share of the facility’s thermal demand.
Combines Standardization With Site-Specific Design
Arcturus is built from standardized subsystems but configured around each facility’s available heat sources, steam requirements, and layout. This combines repeatable equipment design with the site-specific engineering required for industrial heat recovery.
Integrates With Existing Steam Systems
Arcturus installs in parallel with existing boilers, allowing facilities to retain their existing steam capacity for backup and peak demand while using recovered heat for a larger share of normal operation.
Frequently Asked Questions About Industrial Heat Recovery
What industries benefit the most from industrial heat recovery?
Industries with high thermal loads, such as food and beverage, chemicals, pulp and paper, and textiles, tend to see the largest savings from recovering and reusing waste heat.
How much waste heat is typically available for recovery at a manufacturing facility?
Industry-wide, an estimated 20 to 50% of industrial energy input is lost as waste heat, in the form of hot exhaust, cooling water, and heat radiating from hot surfaces and equipment. How much of that heat a given facility can actually recover and reuse depends on the temperature, location, and timing of its available heat sources.
What technologies are used for industrial heat recovery?
Heat exchangers, economizers, waste heat to power systems, and steam-generating heat pumps are among the most common technologies. The right choice depends on the temperature of the available heat and how it needs to be used.
What’s the difference between industrial heat recovery and a heat pump?
Conventional heat recovery technologies, such as heat exchangers or economizers, transfer heat directly from one stream to another and can only move heat from a hotter source to a cooler one.
Heat pumps like Arcturus use mechanical compression to raise the temperature of the recovered heat and generate steam, which allows them to recover heat from lower-temperature sources that conventional heat exchange cannot use directly.
Does installing industrial heat recovery equipment require a facility shutdown?
It depends on the technology and the scope of the retrofit. Some heat recovery projects require tying into existing piping or process equipment, which can require downtime. Arcturus is designed to install in parallel with a facility’s existing boilers, so it can be added without shutting down current steam production.
Does industrial heat recovery reduce exposure to carbon pricing and regulation?
Yes. Because heat recovery reduces how much fuel a facility burns, it also reduces the Scope 1 emissions associated with that fuel use. In regions with carbon pricing or emissions trading programs, this can also reduce a facility’s exposure to those costs.
