Integrated Heat Pump System Research Articles

Integrated heating and cooling system with borehole thermal energy storage for a greenhouse in Romania

The IDA Indoor Climate and Energy (IDA ICE) simulation tool is used to model a research greenhouse in Bucharest, Romania, equipped with a recently implemented energy system that includes an integrated heat pump system, Air Handling Units (AHUs), a dry cooler, and boreholes for thermal energy storage. The integrated heat pump system is designed to provide year-round heating and cooling of the greenhouse. The performance of the system is assessed through simulations conducted for one week in summer (July 2023) and one week in winter (December 2023), using recorded weather data for each respective period. Results from the IDA ICE model are compared with values derived from onsite sensor measurements. During the summer week, the model generally aligns with measured air temperatures in the greenhouse compartment. The total cooling simulated in the model is 26.5 kWh/m2, compared to 27.2 kWh/m2 calculated from onsite measurements. Hourly discrepancies were observed, potentially due to the heat pump system operating at reduced capacity during this summer. In the winter week, the measured and simulated temperatures fall within a comparable range. The calculated and simulated cumulative heating show excellent agreement, both at 15.1 kWh/m2.

Performance evaluation of underground thermal storage integrated dual-source heat pump systems

The increasing demand for electricity stresses the existing electric grids. Buildings consume 73% of all U.S. electricity and are responsible for 30% of U.S. greenhouse gas emissions. Integrating thermal energy storage (TES) in building heating/cooling systems, which consume considerable electricity, can mitigate the challenges to electric grids. This study reports on a novel thermal energy storage device integrated heat pump system to reshape the building electricity demand profile while maintaining thermal comfort. The annual performance of the proposed system has been evaluated through a dynamic system simulation with high fidelity in the Modelica platform. The dynamic model of the novel hybrid component named ‘dual purpose underground thermal battery’ was developed and validated. It was then incorporated into the system model. Given a time-of-use tariff, a rule-based control strategy was designed to shift the electric demand and switch the heat pump source for a typical single-family house in different climate zones of the United States. The system performance of the new TES-integrated dual-source heat pump was compared with that of a conventional air-source heat pump system. The results indicate that the proposed system can reduce the annual HVAC electricity cost by up to 52% while saving 45.2% on electricity consumption. In the Northern areas, the annual peak load of the HVAC system can be reduced by 64.9%. However, this reduction is less in the Southern areas as the system’s higher efficiency in winter dominates the overall energy-saving potential.

Electrification of amine-based CO2 capture utilizing heat pumps

Capturing CO2 is necessary to abate the climate crisis. Amine CO2 capture is the most mature technology but suffers from high thermal energy consumption for solvent regeneration. Heat pumps are a proven technology with which to electrify industrial processes. This study investigates an integrated heat pump system used to electrify an amine CO2 capture unit for a biogas upgrading process using aqueous monoethanolamine. The study evaluates the potential of such integrated systems through the overall energy consumption at varied stripper pressures between 0.313 to 1.813 bara and includes a techno-economic analysis to determine the levelized cost. The most optimal heat pump scenario utilizes a vacuum operated stripper at 0.513 bara and reduces the overall energy consumption by 68 % compared to a classical amine scrubbing unit. The techno-economic analysis shows that the levelized costs for biogas upgrading per MWh of produced biomethane may be reduced by up to 33 % from 47 €/MWh to 31 €/MWh by implementing heat pump electrification systems and a vacuum operated stripper compared to a scenario using natural gas.

Model-based predictive control of multi-stage air-source heat pumps integrated with phase change material-embedded ceilings

This paper presents a model-based predictive control strategy to optimize the operations of phase change material (PCM) ceiling panels coupled with a multi-stage air-source heat pump. A three-stage prototype heat pump unit has been built and tested in the laboratory, with the low and medium stages designed for space heating/cooling and the high compression stage dedicated to charging of the PCM energy storage. To facilitate optimal control of the integrated heat pump system, a mixed-integer linear programming formulation is derived through linearization of the heat pump model and a mixed-integer reformulation of the PCM dynamic governing equations. A predictive control strategy is synthesized based on the resultant control formulation and implemented in a receding horizon scheme that optimizes the PCM charging and the zone temperature schedules simultaneously to leverage both the passive (associated with building construction materials) and active (PCM) storage capacities of a building. The control strategy has been tested along with three benchmarking control scenarios using a co-simulation platform for a prototypical detached house in Atlanta, GA. Test results showed that application of the proposed control strategy to the PCM-integrated heat pump could provide 27.1% electricity cost savings while a fine tuned rule-based control strategy could achieve cost savings of 20.4%, compared to a baseline case without PCM storage, under a time-of-use rate tariff.

Ammonia-based compression heat pumps for simultaneous heating and cooling applications in milk pasteurization processes: Performance evaluation

Ammonia-based heat pumps were investigated to deliver heating (65–95 °C) and cooling (2 °C) simultaneously for the pasteurization of raw milk. Two compression heat pump configurations using a pure refrigerant (ammonia) and zeotropic mixture (ammonia/water) as working fluids were integrated with raw milk pasteurization process: two-stage ammonia compression heat pump with closed intercooler, and two-stage ammonia/water compression heat pump with a solution circuit. The integrated heat pump systems performance simulations were carried out at the base-case design conditions and parametric study on the influence of key operational variables on the system's first- and second-law efficiencies. These heat pumps are attractive and more efficient solutions than current heating and cooling systems used in the dairy processing industries (fossil-fuel-fired boiler and ammonia compression chiller) by up to 59% of a primary energy saving. Besides, the two-stage ammonia/water heat pump operates at a lower system high pressure than the ammonia heat pump, which allows reducing the cost of the system components, especially for the compressor. The development of such types of multi-stage compression heat pumps (with large-temperature-lift) using zeotropic mixture with wide temperature glide, as a working fluid, significantly contributes towards the decarbonization of the dairy processing industry.

Experimental investigation on novel heat pump system for combined drying and air conditioning for arid climate

In an open-loop heat pump dryer, moisture removal in the evaporator is not profitable for an arid climate and hence evaporator may be used for comfort cooling, which leads to an efficient integrated system yielding both heat pump drying and air conditioning with a single energy source. Hence, the present experimental analysis is focused on the design, fabrication, and experimental investigation of an integrated heat pump system for hot and dry atmospheric conditions using future refrigerant R1234yf in the heat pump. The effects of the drying time, air inlet velocity, and inlet temperature to the evaporator and condenser on the energy, exergy, and economic performance of the air conditioning and the drying are investigated. The coefficient of performance for the combined operation is found to be much higher than that for the individual operation (heat pump drying or air conditioning), with an average value of 7.456 for input temperature of 26–45 °C. The average specific moisture extraction rate (SMER) is found up to 2.8 kg/kWh. The total annual profit gain by using the combined system instead of the separate systems is estimated as $309. The cooling air temperature and humidity are in the comfort zone, which confirms the suitability of the system for studied conditions.

Thermodynamic investigations on an integrated heat pump with thermal storage for wind-solar hybrid heating

Heating with wind and solar energy is an effective way to reduce carbon dioxide emissions. Vapor Compression Heat Pumps (VCHP) were generally used to improve the utilization rate of wind power. However, normal VCHP driven by wind power or solar energy has low performances in low temperature environment and low supply temperature of heating water, and it is also difficult to achieve continues and stable heating because of the intermittence of wind power. The present paper introduces a new integrated heat pump system, in which a VCHP absorbs heat from the environment and sends it to an Absorption Heat Pump (AHP) as its low temperature heat source after temperature lift. Thermal storage system is also equipped for continues heating and it serves as the driving force of the AHP. The results show that the integrated heat pump can produce heating water at 50 °C or even higher with a COP of about 1.42 when the environment temperature is as low as −30 °C. Also, the power consumption of the VCHP accounts for only 5%–18% of the total energy input. This indicates that the energy consumed by the integrated heat pump can be mainly from off-peak electricity produced by the wind turbine.

IIoT-Enabled Health Monitoring for Integrated Heat Pump System Using Mixture Slow Feature Analysis

The sustaining evolution of sensing and advancement in communications technologies has revolutionized prognostics and health management for various electrical equipment toward data-driven ways. This revolution delivers a promising solution for the health monitoring problem of the heat pump (HP) system, a vital device widely deployed in modern buildings for heating use, to timely evaluate its operation status to avoid unexpected downtime. Many HPs were practically manufactured and installed many years ago, resulting in fewer sensors available due to technology limitations and cost control at that time. It raises a dilemma to safeguard HPs at an affordable cost. In this article, we propose a hybrid scheme by integrating industrial Internet-of-Things (IIoT) and intelligent health monitoring algorithms to handle this challenge. To start with, an IIoT network is constructed to sense and store measurements. Specifically, temperature sensors are properly chosen and deployed at the inlet and outlet of the water tank to measure water temperature. Second, with temperature information, we propose an unsupervised learning algorithm named mixture slow feature analysis (MSFA) to timely evaluate the health status of the integrated HP. Characterized by frequent operation switches of different HPs due to the variable demand for hot water, various heating patterns with different heating speeds are observed. Slowness, a kind of dynamics to measure the varying speed of steady distribution, is properly considered in MSFA for both heating pattern division and health evaluation. Finally, the efficacy of the proposed method is verified through a real integrated HP with five connected HPs installed ten years ago. The experimental results show that MSFA is capable of accurately identifying health status of the system, especially failure at a preliminary stage compared to its competing algorithms.

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

• Study of an integrated heat pump and thermal storage tank system of a new dairy. • Utilization of high temperature heat pumps with natural refrigerants. • Conducted energy and performance analysis for an energy-intensive week. • Energy and emission savings through extensive waste heat recovery. • Good process integration with total system coefficient of performance of 4.1. 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.

Organizational and technological aspects of the design and construction of heat supply systems based on heat pumps in low-rise construction

There are most of the energy`s costs are accounted for by heating and hot water supply in communal housing conditions. Every day there is a growing need for the development and development of alternative options for energy generation technology. In the field of alternative energy, the most popular solution is a heat supply system based on air heat pumps (HP). Construction and installation work is simplified for integrated heat pump systems, but the question of the organization of design for these devices remains not fully resolved. The purpose of the work is to study the features and patterns of design and construction works with heat pump systems built into the premises in the field of low-rise construction and to develop measures to reduce the time and cost of such works. Heat engineering calculations for integrated heat pump systems that take into account climatic features, architectural and construction elements and parameters of engineering networks of the construction object, increase the complexity, cost and duration of design work. The research methods used are the analysis of the entire design process and in particular the section “heating and ventilation”, further modeling through network planning of the design process and comparison of the obtained data. The results of the study are calendar schedules of the design process of integrated heat pump systems on the example of a cottage structure with an area of 150 m2. For further analysis, the parameters of the time reserves of the working processes of the obtained network graphs are calculated. The section of heating, ventilation and heat supply (S) for integrated heat pump systems of heat supply is compared with the classical one, where the heat generator is an electric boiler. As a result of the study, a scheme for organizing design work is proposed, which allows you to plan the design of the section S without affecting the overall terms of execution of project documentation and the growth of its cost.

Energetic And Exergetic Investigations of an Integrated Heat Pump System for Drying Applications

Energetic And Exergetic Investigations of an Integrated Heat Pump System for Drying Applications

Thermodynamic analysis and performance assessment of an integrated heat pump system for district heating applications

A Rankine cycle-driven heat pump system is modeled for district heating applications with superheated steam and hot water as products. Energy and exergy analyses are performed, followed by parametric studies to determine the effects of varying operating conditions and environmental parameters on the system performance. The district heating section is observed to be the most inefficient part of system, exhibiting a relative irreversibility of almost 65%, followed by the steam evaporator and the condenser, with relative irreversibilities of about 18% and 9%, respectively. The ambient temperature is observed to have a significant influence on the overall system exergy destruction. As the ambient temperature decreases, the system exergy efficiency increases. The electricity generated can increase the system exergy efficiency at the expense of a high refrigerant mass flow rate, mainly due to the fact that the available heat source is low quality waste heat. For instance, by adding 2 MW of excess electricity on top of the targeted 6 MW of product heat, the refrigerant mass flow rate increases from 12 kg/s (only heat) to 78 kg/s (heat and electricity), while the production of 8 MW of product heat (same total output, but in form of heat) requires a refrigerant mass flow rate of only 16 kg/s.

태양열 및 지열 이용 히트펌프 시스템의 성능예측 시뮬레이션에 관한 연구

Recently, the use of renewable energy has been attracted due to the interest in energy-saving and the reduction of CO2 emission. In order to reduce the energy consumption of the cooling and the heating in the field of the architectural engineering, heat pump systems using renewable energy have been developed and used in various applications. In many researches, integrated heat pump systems are suggested which use solar and geothermal heat as the heat source for cooling and heating. However, it is still difficult to predict the performance of the systems, because the characteristic of heat exchange in each system is complicated and various. In this system, the performance prediction simulation of the heat pump was developed using a dynamic simulation model. This paper describes the summary of the suggested systems and the result of the simulation. The average temperature of the heat source, heating loads and COP were calculated with the cases of different local conditions, different system composition and different operation time by TRNSYS 17.

Study on Principle and Application of Heat Pump Technology

This paper studies the low temperature heat source heat pumps to improve the efficiency of the heat pump unit with economic principles and the use of compressed improve the working conditions of the compressor, and to explore the system operating mode. A new test run integrated heat pump system is designed. Heat pump system can be controlled by the intelligent control of the implementing agencies, to improve the economic system, the research of this paper can provide a potential basis for the efficient use of energy heat pump.

Status of not-in-kind refrigeration technologies for household space conditioning, water heating and food refrigeration

This paper presents a review of the next generation not-in-kind technologies to replace conventional vapor compression refrigeration technology for household applications. Such technologies are sought to provide energy savings or other environmental benefits for space conditioning, water heating and refrigeration for domestic use. These alternative technologies include: thermoacoustic refrigeration, thermoelectric refrigeration, thermotunneling, magnetic refrigeration, Stirling cycle refrigeration, pulse tube refrigeration, Malone cycle refrigeration, absorption refrigeration, adsorption refrigeration, and compressor driven metal hydride heat pumps. Furthermore, heat pump water heating and integrated heat pump systems are also discussed due to their significant energy saving potential for water heating and space conditioning in households. The paper provides a snapshot of the future R&D needs for each of the technologies along with the associated barriers. Both thermoelectric and magnetic technologies look relatively attractive due to recent developments in the materials and prototypes being manufactured.

Cool Storage Performance of Integrated Heat Pump System with Triple-Sleeve Energy Storage Exchanger

A new integrated heat pump system with triple-sleeve energy storage exchanger was proposed. Experimental system was designed and developed. The cool storage performance of integrated system was studied. The results showed that evaporating temperature was 1°C which was higher than ice storage. COP of cool storage process at the highest point 2.4 dropped to 1.75. In general, system efficiency kept a high level.

Experimental study on the operating characteristics of a novel low-concentrating solar photovoltaic/thermal integrated heat pump water heating system

Abstract A novel low-concentrating solar photovoltaic/thermal integrated heat pump system (LCPV/T-HP) with both electricity and heat outputs has been developed. A solar photovoltaic/thermal collector with fixed truncated parabolic concentrators reflecting the incident sunlight onto the surface of PV cells also as the evaporator of the heat pump system. Refrigerant, R134a, flows inside the multi-port flat extruded aluminum tubes placed underneath the PV cells, absorbing solar heat and evaporating. Refrigerant’s condensing heat is used to heat water in condenser. Experiments on the novel LCPV/T-HP system were carried out in Nanjing, China, and its operating characteristics evaluated using an LCPV system without being cooled as a benchmark. Experimental results showed that the LCPV/T-HP system achieved an averaged COP of 4.8 for heating water from 30 °C to 70 °C on a sunny summer day, with an output electrical efficiency of 17.5%, 1.36 times higher than that of the LCPV system. Furthermore, the experimental results suggested that flux concentrating rate of the fixed parabolic concentrators was 1.6. Finally, the influences of PV cells’ operating temperature on the photovoltaic output characteristics were analyzed, and an optimized control method to achieve a higher power output and electrical efficiency was further discussed.

Möglichkeiten zur energetischen Optimierung biotechnologischer Massenproduktionsprozesse am Beispiel der Futterhefeanlagen der DDR

AbstractCalculations have been made with the aim of utilizing the waste heat released at constant rates in the large‐scale production of fooder yeast in the G.D.R. and as yet unused, for thermally concentration of fermentation products. The following results were obtained, based on left‐handded thermodynamic cycles and corresponding with the largest production plants working in the G.D.R.There is the prospect of integrated heat pump systems with direct exposure of evaporator and condenser surfaces and steam‐driven compressors supersending conventional, steam‐heated concentration systems. There is, however, a major hazard in the form of possible breakthroughs of refrigerants into the biosuspension. Processes involving what is known as vaporization cooling and operating without specific refrigeration cycles can presently not compete with conventional systems.None of the two versions can make full use of the waste heat from fermenters for thermal processing. Recovering between 20 and 30% would be an economical proposition.