A company specializes in poultry slaughtering and processing, operating in two shifts with a daily slaughter capacity of approximately 270,000 chickens. The processing steps, such as scalding, cooking, and high-temperature sterilization, require significant steam consumption, exceeding 38 tons per day, all of which is purchased at a cost of 330 RMB/ton. This reliance on external steam sources results in high operational costs. Moreover, cooling, freezing, and storage of the finished products require a refrigeration system that uses steam for heating and compressors for cooling. The lack of integration between heating and cooling processes leads to considerable energy waste.

Requirements
The client requested a solution utilizing the condensation heat from an ammonia refrigeration system as the heat source. The system operates at 35°C saturation temperature in summer and 25°C in winter. The heat is needed for production processes in the workshop, requiring hot water at 65°C and 95°C. The 65°C water is used for scalding, spraying, and cleaning, while the 95°C water is used for high-temperature cooking and sterilization. The client aimed to recover condensation heat from the ammonia refrigeration system and use heat pumps to produce the required hot water.

Hot Water Demand:

• 65°C water: 570 tons/day, peak demand 45 tons/hour

• 95°C water: 240 tons/day, peak demand 10 tons/hour

System Design

The project employs two ammonia high-temperature heat pumps and two R245fa high-temperature heat pumps, along with auxiliary equipment, including preheaters, replenishment tanks, and thermal storage tanks for 65°C and 95°C water.

Process Overview:

• The system first recovers condensation heat from the ammonia refrigeration system using the ammonia heat pump units to produce 65°C hot water, which is stored in the 65°C tank.

• A portion of this 65°C water is directly supplied to the workshop for scalding and other processes, while the rest serves as the heat source for the R245fa heat pumps, producing 95°C water for high-temperature processes.

• Both storage tanks provide thermal buffering, and water is supplied to end-users as needed.

Capacity:

• Maximum production: 800 tons/day of 65°C water, 400 tons/day of 95°C water.

• The system fully replaces the need for purchased steam.

Technical Specifications
The two-stage heat pump system was designed to meet the specific requirements for 65°C and 95°C hot water. Heat recovery from the refrigeration system's condensation heat ensures adequate capacity. During summer, the system's maximum heat discharge reaches 13,000 kW, while in winter, it averages 3,500 kW—sufficient to meet the heat recovery needs.

Performance and Benefits

Energy Savings:

• The system delivers 31,257 GJ of heat annually, consuming only 2,347,700 kWh of electricity (annual cost: 1.526 million RMB, based on 0.65 RMB/kWh).

• By replacing purchased steam (previous cost: 330 RMB/ton), the system saves 12,210 tons of steam annually, equivalent to 4.029 million RMB in steam costs.

• Annual cost savings: 2.503 million RMB.

• Payback period: 2.5 years.

Environmental Impact:

• Reduction of 3,125 tons of CO2 emissions annually.

• Recovery of 24,192 GJ of condensation heat per year, avoiding thermal pollution.

• Significant contribution to environmental sustainability through efficient energy utilization.

Client Feedback:

The system has been operating stably for over four years, recovering a total of 96,768 GJ of condensation heat, saving 22,000 tons of water, and reducing CO2 emissions by 12,500 tons.

Economic benefits exceed 10 million RMB, with stable system performance and outstanding energy-saving results.

The project demonstrates the feasibility and advantages of using high-temperature heat pump systems for full heat recovery in refrigeration, offering a replicable model for broader application.