Techno-Economic Optimization of Heat Pump-Based Heating Systems Utilizing Heat Extraction from Watercourses

Abstract

The paper examines the techno-economic aspects of implementing heat pump units (HPUs) in heating systems based on the utilization of low-grade heat (LGH) from natural water sources, particularly river watercourses. Heat pump systems can efficiently use natural resources to meet energy demands, which is a crucial factor in reducing energy consumption and minimizing environmental impact. The advantages of employing a closed-loop heat extraction system with a circulating antifreeze heat transfer fluid are substantiated, ensuring reliable system operation during winter and reducing the risk of ice formation in heat exchangers.

Several design configurations of heat exchangers for extracting heat from aquatic environments are presented. These configurations enhance heat transfer efficiency and reduce hydraulic losses in the system. The study also analyzes the drawbacks of conventional bottom collectors made from polyethylene pipes, including their high material consumption, complex installation, and susceptibility to clogging, which ultimately reduces overall system efficiency. As an alternative, the use of tubular grates oriented perpendicular to the flow direction is proposed. This approach improves heat exchange, reduces hydraulic resistance, and enhances heat extraction efficiency by increasing the contact surface area between the heat transfer fluid and the water environment. Such a solution significantly reduces the system’s operational costs and ensures a more stable and reliable heating process.

The research addresses key parameters such as hydraulic resistance, material costs, optimal heat transfer fluid selection, and other operational characteristics that impact the overall economic efficiency of the system. A techno-economic optimization problem for the heat exchanger design is formulated, considering two variables — pipe diameter and total pipe length. The optimization criterion is the minimization of the system’s payback period compared to a baseline option of direct electric heating. Mathematical model is developed to determine economically feasible design parameters for the heat exchanger, accounting for HPU performance, capital investment, and potential energy savings. Conclusions are drawn regarding the potential for widespread adoption of river-sourced heat pump systems in sustainable heating practices, highlighting their capacity to reduce energy costs and environmental impact.