Inverter Heat Pumps as a Variable Load for Off-Grid Solar-Powered Systems

Abstract

The capacity of electric air conditioning and heating systems is growing rapidly, as is the nameplate capacity of PV power plants. While the demand for cooling has a positive correlation with solar irradiance, the demand for heating has an opposite relation. In this study, different approaches to design (aggregation; thermal, battery, and implicit storage) and control (frequency conversion; variable and adaptive load) and their effects on the efficiency of an off-grid active thermal stabilisation system based on a solar-powered heat pump are analysed. The case considered is a permafrost thermal stabilisation system in Norway. It is shown that proper layout and control of the system with an adaptive load can reduce capital expenditures and the total cost of ownership by 30–40%. Increases in the capacity factor and cooling stability of the systems with aggregated and variable loads are studied. The downside is that there is an increase in the compressor’s operation time by 50% with a variable load and by 25% per unit with aggregation, which means more frequent replacement in terms of motor hours. The approaches considered are applicable in a wide range of solar-powered facilities with a positive correlation between solar irradiation and energy demand, but the results are quite case-sensitive. The prospects of using excess refrigerant and soil for thermal energy storage instead of traditional electrochemical batteries are considered.

Proceedings of the 12th International Conference on Permafrost: Volume 2 (Conference Papers)

“…Site 1 had a straight layout with battery storage for solar power output intermittency compensation and a start-stop heat pump. High battery cost and its fast degradation due to intense cycling had led us to using invertor heat pumps as a variable load that follows actual power ouput (Klokov et al 2023a;Tutunin and Loktionov 2023) for sites 2 and 3.…”

Optimizing Multi-Layer Perovskite Solar Cell Dynamic Models with Hysteresis Consideration Using Artificial Rabbits Optimization

“…The d-burrows are generated along each dimension by Equation (10) in the vicinity of a rabbit. The hiding parameter is represented by H and is reduced in a linear manner from 1 to 1/T over the course of the iteration with a random perturbation.…”

“…Solar energy harnesses the sun's radiant heat and light to generate electricity, facilitate solar architecture, and produce thermal energy [10]. As a prominent renewable energy source, solar energy systems are categorized into active or passive solar based on their energy capture, distribution, and conversion mechanisms.…”

AC-DC-DC Converter for Small Power Energy Storage Systems

“…Currently, various types of energy storage technologies are available, including electrochemical batteries, heat or cold storage systems, kinetic energy, or other carriers. Promising technologies in the realm of energy storage include recycled batteries, supercapacitors, hybrid supercapacitors, sodium-ion batteries, flow batteries, and small hydrogen fuel cells [32][33][34][35][36][37][38][39][40]. However, due to their prevalence, commercial availability, and cost-effectiveness, electrochemical batteries are the most popular, especially lithium-ion and valve-regulated Due to the number of possible operating modes and scenarios and the possibility of providing additional demand-side response (DSR) services to the grid operator, the complexity of such a system is high and requires the use of a supervisory control system.…”

“…Currently, various types of energy storage technologies are available, including electrochemical batteries, heat or cold storage systems, kinetic energy, or other carriers. Promising technologies in the realm of energy storage include recycled batteries, supercapacitors, hybrid supercapacitors, sodium-ion batteries, flow batteries, and small hydrogen fuel cells [32][33][34][35][36][37][38][39][40]. However, due to their prevalence, commercial availability, and costeffectiveness, electrochemical batteries are the most popular, especially lithium-ion and valve-regulated lead-acid (VRLA) batteries.…”