Waste Heat Utilization in Industrial Processes

The utilization of waste heat from industrial processes, such as cooling towers, can significantly increase overall energy efficiency. 🌍

Waste Heat Potential

Medium/low temperature waste heat is crucial to decarbonize the thermal demand of many industries (textile, food, paper, chemical, etc.). One potential use is its conversion into steam, essential for industrial activities such as electricity generation, sterilization, food processing and air conditioning.

Cooling Towers and Water Consumption

Cooling towers dissipate heat from the circulating fluid, but consume between 2 and 5 m³ of water for each MWh transferred, which can be limiting in times of water stress. 💧

Proposed Solution: High Temperature Heat Pump

Installing a high temperature heat pump in industrial processes can:

• Replace cooling towers and their water consumption.
• Produce steam, increasing electricity production in the cogeneration turbine.

Study Analysis

The study analyses the use of a low temperature waste heat stream (60-70°C) to produce steam using a high temperature heat pump based on a reverse Brayton cycle with CO2. This solution allows:

• Cooling the hot water stream, eliminating towers and saving water.
• Achieving a lower water outlet temperature, facilitating its treatment.
• Producing process steam, eliminating an extraction from the cogeneration turbine and generating additional electricity.

Study Results

Two main scenarios are considered based on the available waste heat and steam generation conditions. Under the best conditions, a COP of 2.03 is achieved. The plant has dimensions of 21m x 21m x 25m and requires an investment of €44,383,762, with a cost of €611/kW.

Costs and Economic Viability

• Heat costs (LCOH): €51/MWh to €62/MWh.
• Operating costs (OPEX): €43.5/MWh to €46/MWh. These costs are competitive with ETES systems, set at €75/MWh in 2023, with a target of €63/MWh in 2030.

To find out all the details and go deeper into the analysis, you can download the full article. 📥 Don't miss it!