Integrated high temperature heat pumps and thermal storage tanks for combined heating and cooling in the industry

Abstract

This study investigates the integrated heat pump system of a green-field dairy located in Bergen, Norway. The purpose of the study is to determine the energy consumption and system performance. The dairy features a novel and innovative solution of a fully integrated energy system, employing high temperature heat pumps such as the hybrid absorption-compression heat pump (HACHP) with natural refrigerants to provide all temperature levels of heating and cooling demands. To evaluate the performance an energy analysis has been performed based on available process data for a comparatively energy-intensive week in February. The results have shown that the integrated system is able to meet the occurring demands. Furthermore, the specific energy consumption with 0.22 kWh l − 1 product can outperform the annual average value of the replaced dairy even under difficult conditions. However, it is expected that the specific energy consumption will be further reduced on an annual basis. Through measures such as the extensive use of waste heat recovery accounting for 32.7% of the energy used, energy consumption was reduced by 37.9% and greenhouse gas (GHG) emissions by up to 91.7% compared to conventional dairy systems. Simultaneous, the process achieves a waste heat recovery rate of over 95%. Furthermore, demand peaks were compensated and a system coefficient of performance (COP) of 4.1 was achieved along with the identification of existing potential for further improvements.

A review of thermal energy storage technologies for seasonal loops

“…Inlet temperatures are dependent on the heat sources used in conjunction with the thermal storage as well as the use or non-use of heat pumps. Solar collectors, bio-mass boilers, and industrial waste heat are often employed as heat sources, generating charging temperatures between 70 -95 °C [64,93,94,95]. As a result of the high storage temperatures, the stored heat is commonly utilised through district heating schemes [57,64,94].…”

Numerical Investigation of an Oil-Free Liquid-Injected Screw Compressor with Ammonia-Water as Refrigerant for High Temperature Heat Pump Applications

“…The use of high temperature heat pumps with natural working fluids, such as ammonia and water, instead of conventional boilers is an effective measure to exploit available waste heat while reducing the consumption of energy and dependency of fossil fuels, as outlined by Bergamini et al [5] in a thermodynamic system comparison. Ahrens et al [6] supported this statement by presenting operational performance results of an integrated energy system of an existing dairy plant, using heat pumps entirely for all cooling and heating applications. Many authors such as Arpagaus et al [7], Kosmadakis [8], Marina et al [9], and Jiang et al [10] investigated and summarized the possibilities of using high temperature heat pumps and found great potential for the application in various industrial sectors for the supply of process heat with sink temperatures above 100 • C.…”

Identification of Existing Challenges and Future Trends for the Utilization of Ammonia-Water Absorption–Compression Heat Pumps at High Temperature Operation

“…In recent years, there has been a growing demand in the utilization of ACHPs with ammonia-water as working fluid for high temperature industrial applications [18,25]. The research focuses on achieving higher sink temperatures and system efficiencies to increase the suitable application range and competitiveness compared to VCHPs and conventional solutions.…”

“…During the installation of further test and pilot plants, the ACHP with a single-stage solution circuit was successfully brought to commercial implementation using standard refrigeration components [22,23]. Until today, several units have been installed for commercial use in various industrial applications, achieving heat sink temperatures of up to 120 • C and temperature lifts of up to 75 K [24,25].…”