Heat Pump Applications Research Articles

Application of transcritical CO2 heat pumps to boiler replacement in low impact refurbishment projects

80% of current UK housing stock is expected to still be in use in 2050. Difficult, intrusive and expensive, refurbishment measures are required to achieve the level of insulation required for current low temperature heat pumps. Transcritical CO2 heat pumps can achieve higher efficiencies, with higher output temperatures, than current, Carnot limited, synthetic gas heat pumps, with less environmental impact. Widely deployed in water heating and supermarket chilling systems, CO2 heat pumps need heating return temperatures of 30 °C or less to function effectively. This has impeded their adoption with hydronic heating systems which have high return temperatures.This study identified system modifications external to the refrigeration cycle that address return temperatures. It modelled a transcritical CO2 air source heat pump with a hydronic heating system in a solid wall semi-detached house. Full year system coefficients of performance over 3 were achieved in four UK locations by using space heating return fluids to defrost the air source heat exchanger and to pre-heat inlet water, recovering any remaining excess return fluid heat as a source for the heat pump. Solar panels boosted this to 5.1. The levelized cost of energy for the system was calculated (with heat pump grant) at 22p/kWh, lower than a gas boiler, with 9.45 tonnes CO2 emission savings over a fifteen-year life.

Isothermal (vapor ＋ liquid) equilibrium measurements and correlation of the binary mixture 3,3,3-trifluoropropene (R1243zf) ＋ isobutane (R600a) at temperatures from [formula omitted] to [formula omitted] K

The restrictions set by the F-gas Regulation and the Kigali Amendment to the Montreal Protocol have pushed an extensive research into alternatives for fluorinated greenhouse gases in air conditioning and refrigeration. Hydrofluoroolefins (HFOs) are emerging as promising substitutes for hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) in HVAC and refrigeration. Amongst these, R1243zf raised interests as low-GWP substitutes for R134a. The pursuit of low GWP refrigerants has also led to the examination of hydrocarbons (HCs), like propane (R290) and isobutane (R600a), due to their efficiency, low charge, and affordability, despite their flammability. The mixtures of R1243zf and isobutane could be of interest for medium temperature heat pump applications. Moreover, blending HFOs with HCs usually leads to azeotropic mixtures. While HCs benefit of a wide range of data and reliable Equations of State (EoS), HFOs, and in particular their mixtures, lack comprehensive information. This study reports vapor–liquid equilibrium (VLE) measurements for the 3,3,3-trifluoropropene (R1243zf) + isobutane (R600a) binary system in the temperature range between 283.15 K and 323.15 K. The measurements have been carried out by means of a vapor-recirculation apparatus combined with gas-chromatographic analysis. This work reports 53 experimental data with an expanded uncertainty (k=2) of 0.003 mol mol−1. The reported data, along with the data available in the literature, have been used to developed two new mixture models based on the Helmholtz free energy EoS, both leading to a significant improvement in the VLE prediction, with RMSE values lower than 0.005 mol mol−1 for both the liquid and the vapor phase composition.

Application of heat pump drying technology to produce dried mango products from Tu Quy mango (Mangifera india L.), Vietnam, on a pilot scale

In this study, the heat pump drying technique was applied to develop the production process of dried mango from Tu Quy mango sources, Ben Tre province, Vietnam. The experiment was performed in three steps. First, mango slices were treated through the blanching process. Samples were pretreated with sizes from 6 to 12 mm at 80–95°C for 3–6 min, and then the mango slices were soaked in a syrup solution concentration range of 25–40°Bx, citric acid of 0.5–2%, and glycerol of 0.1–0.4% at 35–65°C for 90–180 min. Finally, the samples were dried using a pilot-scale heat pump dryer until the moisture content reached 14–16%. The results showed that the blanching and osmosis processes were carried out under optimal conditions to inactivate the Polyphenol oxidase (PPO) enzyme, obtain maximum polyphenol compounds, and conform to the product appearance. Additionally, the drying process was carried out at 30°C for 1,080 min with the polyphenol content retaining 11.71 mgGAE/gDW—This signifies a successful endeavor in developing production methodologies and expanding the range of mango-derived products. Employing innovative technological processes enhances both the quantity and quality of the products. Moreover, the manufacturing procedure was executed on a pilot device, streamlining the synchronization of large-scale production processes effortlessly. This advancement not only enhances economic value but also addresses the issue of congestion prevalent in the current state of the mango industry in Vietnam.

Performance of Heat Pump Air Conditioning with R1234ze (HFO) as a Refrigerant

The study shows that refrigerants R1234ze (E) and R1234ze (Z), known for their low global warming potential, are likely to become primary choices in heat pump air conditioning for residential and commercial use. The research evaluates the thermodynamic properties of R1234ze (Z) using experimental, thermodynamic, and numerical analyses. It addresses F-gas regulation requirements and aligns with the Paris Agreement goals by exploring various refrigerants, including R227ea, R114, R236fa, R134a, R1234ze (Z), and R245fa, as potential candidates for evolving industry needs. The analysis indicates that R1234ze (Z) outperforms other working fluids in heat pump applications, with an optimized theoretical coefficient of performance (COP) at a condensation temperature 22 K lower than critical temperatures. However, actual COP deviates due to a significant pressure drop, especially with inadequate volumetric capacity. A key finding is that a substantial portion of the pressure reduction is attributed to mitigating irreversible losses, estimated at a condensation temperature of 70–75°C, emphasizing the complex relationship between pressure and performance. The study suggests that R1234ze (Z) is more suitable for high-temperature applications than traditional air conditioning systems. In a parallel assessment, the initial calculation of the coefficient of performance for R245fa evaluates the reliability of a new refrigeration industry arrangement. Test results for heat pump technology reveal that R1234ze (Z) achieves an impressive COP of up to 3.60 at a buildup temperature of 90°C with a temperature differential of 45 K. This positions R1234ze (Z) as a suitable choice for heat pump applications prioritizing simplicity in system design.

Brazing of Copper Pipes for Heat Pump and Refrigeration Applications

In heat pumps and refrigeration systems, copper parts play a crucial role. Since heat pumps for space and water heating work under high pressure and are susceptible to vibrations, it is crucial to perfectly weld the copper pipes and heat exchangers to avoid system failures and prevent the leakage of the circulating refrigerants, which are harmful to the environment. The welding of the copper pipes is usually performed by the brazing process in a furnace. The components are subjected to a period of approximately 50 min inside a continuously open oven, varying the temperature from 710 °C to 830 °C. The oven inlets and outlets are protected by nitrogen curtains to guarantee a suitable internal environment and prevent the contamination of the gas inside the oven. This work analyses which welding methods are most suitable for welding copper, the best joint shape, process time, brazing specimens of a copper alloy, tightness tests, and mechanical properties and composition of the welding samples. From the tests carried out, the appearance of small and large defects is reduced by using a 1 mm thick external ring of filler material and a brazing temperature of 820 °C.

Performance of vacuum-insulated central pipes for deep borehole heat exchangers in geothermal systems

Abstract Geothermal energy is considered a promising future energy prospect, with the geothermal well outlet temperature being one of the important parameters affecting possible utilization options. For ground source heat pump applications or direct district heating, using lower temperatures can be acceptable. However, efficient electricity production requires a higher enthalpy gradient, which cannot be achieved without high temperature at the wellhead. The selection of the dry co-axial close-loop deep borehole systems (DBHE) may be, in some cases, very beneficial. The operating performance of co-axial DBHE can be optimized if the undesired heat transfer between the central pipe and annular fluid zones is minimized. Therefore, the operational performance of such a system depends strongly on the high thermal resistance of the central pipe. The most common option would be a low thermal conductivity material, such as high-density polyethylene (HDPE). In addition, vacuum-insulated tubing (VIT) used as the central pipe could be considered. The article presents results from the study aimed at the comparison of the homogeneous central pipe made of HDPE material and the gap-insulated central pipe. In the study, various air pressure levels as well as variations of surface emissivity were examined to reveal the effect on the heat transfer between the fluid channels. The simulation has been performed using a new purposely developed WellTH simulation software. A coaxial heat exchanger system using a VIT outperforms significantly the heat exchanger with an HDPE for deep geothermal wells. However, this advantage diminishes for shallow wells and therefore this tendency should be considered in the design stage.

Potential assessment of biomass-based single-stage adsorption systems for refrigeration, cooling, and heat-pumping applications

ABSTRACT This article presents the performance estimation of a single-stage vapor adsorption system employing various carbon-based adsorbents with ethanol refrigerant, coupled with a small-scale biomass-based heating unit for space cooling, refrigeration, and heat-pumping applications. A detailed parametric investigation highlights the effects of operating temperatures, and heat exchanger to adsorbent mass ratio on specific cooling energy (SCE), coefficient of performance (COP), uptake efficiency (ηu), and mass of adsorbent to combustion fuel (mad/mcf) to identify the suitable adsorbent and sorption bed designs for each application. The numerical findings reveal that the flat-finned tube (FFT) adsorber outperforms traditional-finned tube (TFT) and tube & shell-type (T&S) adsorbers, achieving 19% and 30% higher COP, respectively, with biomass carbon-ethanol pair. The H2-treated Maxsorb-III shows the greatest optimal cooling COP (0.73), followed by the biomass-carbon (0.72) for refrigeration and space cooling. For heat pumping applications, biomass carbon-ethanol achieves the highest heat pumping COP (1.84) at a desorption temperature of 90°C, surpassing H2-treated Maxsorb-III. Further, the biomass-derived activated carbon requires the lowest amount of adsorbent per unit mass of combustion fuel in the biomass heating unit. The present thermodynamic analysis is a precursor for optimization of the potential heat-exchanger geometries and operating parameters, with the high-performance carbon adsorbents.

Research on the Application of Heat Pump with Different Coupling Methods in Heating Terminal

Under the dual pressure of energy supply and demand contradiction and increasingly severe environmental pollution, adopting clean energy to replace traditional fossil energy, reducing conventional energy consumption, and achieving clean heating is a necessary measure for China to build a resource-saving and environmentally friendly society. In order to achieve the above goals, heat pump technology is receiving attention and promotion from people. Analyze the application of solar and air source heat pump combined heating systems and water source heat pump and air source heat pump combined heating systems based on the comparison of two coupling methods and temperature distribution at different heating ends.

Research progress and applications of transcritical carbon dioxide heat pumps: A review

Heat pump technology is an energy-saving technology that can efficiently utilize low-grade energy. It has broad application prospects in building heating, industrial waste heat utilization, new energy and other fields. However, the refrigerants used in traditional heat pump systems have serious negative impacts on the environment, and there is an urgent need to find a safe, environmentally friendly, and efficient alternative refrigerant. As a natural refrigerant, CO2 has good physical and chemical properties and is very suitable as a working fluid in transcritical cycles, showing great advantages in the field of heat pump technology. At present, research on CO2 heat pumps has made certain progress, but there are few reviews of the research status and development trends of CO2 heat pumps in different applications. Therefore, this article systematically summarizes the latest research results of transcritical CO2 heat pumps in different application fields, pointing out the difficulties such as high pressure and low operating efficiency in system design and operation. It also summarizes the latest optimization research on system components, cycle structure, mixed refrigerants and control strategies. The results show that each optimization method can significantly improve system performance, among which mixed refrigerant is the simplest optimization method. Finally, the outlook for CO2 heat pump technology is put forward. With policy support and technological advancement, more comprehensive, energy-saving, and intelligent CO2 heat pump technology will continue to develop and innovate.

Data-driven compressor performance maps and cost correlations for small-scale heat-pumping applications

The performance of vapour-compression heat pumps depends crucially upon compressor selection and design. In this work, a unified modelling framework is developed to enable technoeconomic comparisons of compressors intended for small-scale heating applications (<30 kWth). Published information on 120 commercially available compressors is analysed and used to develop performance maps that predict isentropic efficiency over a wide range of working conditions. Additionally, cost correlations are established to predict price as a function of nominal compressor inlet volumetric flowrate. When rotary-vane compressors are an available option (i.e., for inlet volumetric flowrates up to 5 ∙ 10−3 m3/s), they consistently achieve a high isentropic efficiency (∼70 %) for the investigated pressure ratios (1.5–9.5). Scroll compressors have an even higher isentropic efficiency (∼75 %) at pressure ratios below 5.5, but this drops to 50 % at higher pressure ratios, while the isentropic efficiency of reciprocating-piston compressors is best (∼75 %) at higher pressure ratios (5.5–7.5). Utilising an air-source heat pump model, the compressor types are compared for countries with different weather characteristics and electricity prices. Rotary-vane compressors are associated with the lowest levelised cost of heat, but the comparison largely depends on location and heating requirements.

Machine Learning Assisted Microchannel Geometric Optimization—A Case Study of Channel Designs

At present, microchannel heat exchangers are widely applied in the fields of air-conditioning and heat pumping applications given their high heat transfer performance, compact size, and low material cost. However, designing and optimizing the channel geometries remain challenging, as they require balancing multiple competing objectives to achieve the optimal performance. This study investigates various parameters, including the channel count, wetted perimeter, cross-sectional area, and mass flow rate for each channel, to achieve the optimal efficiency. The optimization objectives include maximizing the heat transfer rate, minimizing the refrigerant convective thermal resistance, maximizing the refrigerant heat transfer coefficient, and minimizing the pressure drop. A multi-objective genetic optimization algorithm, in conjunction with artificial neural network (ANN)-based machine learning models, was used to predict the heat transfer rate to speed up the calculation process during the optimization. We identified that a gradient reduction in the wetted perimeter from the air inlet along the airflow direction could enhance the heat transfer rate. Additionally, the results indicate that an increase in the number of channels leads to an enhanced heat transfer efficiency rate. However, with the increase in the number of channels, the cross-sectional area of each channel is correspondingly reduced to maintain a consistent overall cross-sectional area. This reduction increases the fluid resistance, leading to an increased pressure drop across the system. This observation is critical for a microchannel design optimization, highlighting the importance of attaining a balance between achieving a higher heat transfer efficiency and maintaining a favorable fluid dynamic performance.

Giant magnetocaloric effect for (Mn, Fe, V)2(P, Si) alloys with low hysteresis

The Fe2P type Mn–Fe–P–Si alloys exhibit a giant magneto-elastic first-order transition, but the large hysteresis limits their performance. Crystal structure evolution and magnetocaloric performance were investigated by varying the Mn and Fe contents at a constant V substitution of 0.02 in Fe2P-type (Mn1.17-xFe0.73-yV0.02) (P0.5Si0.5) (where x + y = 0.02). The V substitution of Fe content shows a larger reduction of hysteresis compared with the same substitution amount of Mn content. During magnetoelastic phase transition, V-substitution reduces the volume change and the volumetric stresses, providing a superior mechanical stability. Compound with the V substitution of Fe (y = 0.02) shows the best magnetocaloric effect with a low thermal hysteresis of 0.6 K. Our developed Mn1.17-xFe0.73-yV0.02P0.5Si0.5 alloys are excellent materials for room-temperature magnetic heat-pumping applications by using a permanent magnet.

Heat exchanger circuitry optimization using an enhanced integer permutation-based genetic algorithm in low-GWP reversible heat pump applications

Tube-fin heat exchangers (HXs) are key components in air-conditioning and heat pump applications. Advanced heat exchanger design optimization tools are desired to adapt to the industrial transition from conventional refrigerants to low Global Warming Potential (low-GWP) refrigerants. The performance of heat exchangers is strongly influenced by the refrigerant circuitry. This research presents an enhanced integer permutation-based Genetic Algorithm (IPGA) to optimize the circuitry of tube-fin heat exchangers. To remedy the limitation of the previous IPGA, which cannot generate designs with splitting and merging of circuits, a new chromosome, as well as new generic operators, are developed. The enhanced IPGA uses effective chromosome representations and GA operators to guarantee the chromosome (genotype) can be mapped to valid heat exchanger designs (phenotype) and incorporates real-world manufacturability constraints to ensure the optimal designs are manufacturable with the available tooling. Previous circuitry optimizations focus on improving component-level performance under a specific operating condition, i.e., the heat exchanger either works as a condenser or an evaporator. The optimal circuitry obtained under air conditioning (AC) mode cannot guarantee optimal performance when used in heat pump (HP) mode. To improve the dual-mode performance of reversible heat pumps, a bi-objective optimization problem formulation is implemented to achieve optimal system performance in both AC and HP modes. A case study using six refrigerants, i.e., R410A, R452B, R454B, R32, D2Y60, and L41a, shows that optimal heat exchangers yield up to 6.1 % energy efficiency ratio (EER) improvement under AC mode and up to 8.5 % coefficient of performance (COP) improvement under HP mode. The use of this design approach can ensure a preferable performance of reversible heat pumps during both cooling and heating modes.

4E analyses of a novel solar-assisted vapor injection autocascade high-temperature heat pump based on genetic algorithm

Insufficient heating performance is one of the main obstacles that inhibit the widespread application of autocascade heat pump. Therefore, a novel solar-assisted vapor injection autocascade high-temperature heat pump is put forward, which owns two working modes to take full use of solar energy and air energy. At first, the performance variations of the novel system with key operating parameters are theoretically investigated to assess the system characteristics. Thereinto, under considered condition, SV mode is more appropriate to the novel system than VA mode under over 200 W m−2 solar radiation intensity. And then, the energy, exergy, economic and environmental performance of the novel system, vapor injection autocascade heat pump and convenient autocascade heat pump is conducted based on genetic algorithm. The novel system respectively increases the maximum heating COP and corresponding heating capacity by averages of 16.5 % and 18.1 %, in comparison with the vapor injection autocascade heat pump. The irreversibility distributions in three systems are also analyzed. Moreover, the novel system produces the lowest full life cycle cost and air pollutant emissions among three systems. Under given application scenario, the payback period is 2.06 years and 2.95 years when the novel system is adopted to replace other two systems.

Performance enhancement of hybrid absorption-compression heat pump via internal heat recovery

Heat pumps, especially the air-source systems, have been regarded as promising technology for deep decarbonization of thermal energy, but its industrial application is strongly constrained by its small temperature lift. Three-stage hybrid absorption-compression heat pump cycles have been proven as an effective way to achieve large temperature lift, but suffer from performance degradation under high temperature lift. In this study, different internal heat recovery configurations for the three-stage hybrid cycle are investigated for performance enhancement under high temperature lift. Results show that the three-stage hybrid cycles with internal heat recovery can reach output temperature of 100–190 °C with COP of 1.26–2.23, under the ambient temperature of 30 °C. By effectively recovering the condensation heat of absorption sub-cycle, the maximum output temperature and maximum temperature lift of three-stage hybrid cycles are increased by 10 °C and 20 °C, respectively, and the COP under 100 °C temperature lift is improved by 13 %. More importantly, sub-zero operation of the three-stage hybrid cycle is enabled by the internal heat recovery. The comprehensive enhancement of three-stage hybrid cycle with internal heat recovery shows the great potential in promoting the industrial application of air-source heat pump.

Low-Cost Distributed Thermal Response Test for the Estimation of Thermal Ground and Grout Conductivities in Geothermal Heat Pump Applications

The design process of a borehole heat exchanger (BHE) requires knowledge of building thermal loads, the expected heat pump’s COP and the ground’s thermophysical properties. The thermal response test (TRT) is a common experimental technique for estimating the ground’s thermal conductivity and borehole thermal resistance. In classic TRT, a constant heat transfer rate is provided above ground to the carrier fluid that circulates continuously inside a pilot BHE. The average fluid temperature is measured, and from its time-dependent evolution, it is possible to infer both the thermal resistance of the BHE and the thermal conductivity of the ground. The present paper investigates the possibility of a new approach for TRT with the continuous injection of heat directly into the BHE’s grouting by means of electrical resistance imparted along the entire BHE’s length, while local (along the depth) temperature measurements are acquired. This DTRT (distributed TRT) approach has seldom been applied and, in most applications, circulating hot fluid and optical fibers are used to infer depth-related temperatures. The distributed measurements allow the detection of thermal ground anomalies along the heat exchanger and even the presence of aquifer layers. The present paper investigates the new EDDTRT (electric depth-distributed TRT, under patenting) approach based on traditional instruments (e.g., RTD) or one-wire digital sensors. The accuracy of the proposed method is numerically assessed by Comsol Multiphysics simulations. The analysis of the data obtained from the “virtual” EDDTRT confirms the possibility of estimating within 10% accuracy both thermal ground and grout conductivities.

Dehumidification load ratio: influence mechanism on air conditioning and energy saving potential analysis for building cooling

The construction energy consumption (EC) makes up around 35% of the total energy used. Half of this energy is used for air-conditioning to cool spaces. The effectiveness of cooling relates to various factors, particularly the dynamic thermal performance of air-conditioners (AC) in different conditions. Studying heat pumps in diverse hot and humid climates, especially where dehumidification matters in summer AC, reveals efficiency. Examining the connection between coefficient of performance (COP) and heat removal aids in lowering building energy usage and improving cooling systems. To achieve this, a validated thermodynamic model of heat pumps and a specific transient building heat transfer model were combined. The study focused on three distinct hot and humid climate zones: Guangzhou, Wuhan, and Jiuquan. Simulations of heat pump performance were conducted throughout the year to analyze variations in COP, relative humidity (RH), and latent heat load (LHL).Key findings indicate that the COP of heat pumps is notably influenced by the practical amount of dehumidification required. A positive correlation (correlation coefficient: 0.52151) exists between COP and LHL, emphasizing the importance of addressing dehumidification needs. The research highlights that the COP remains consistently high when the heat pump manages between 45% to 80% of the LHL. Practically, these findings have crucial implications for heat pump applications and building EC reduction, particularly in regions with pronounced dehumidification requirements during the cooling season. By understanding the interplay between heat pump efficiency, humidity, and heat load, practitioners can optimize heat pump performance to achieve energy savings. This research provides a valuable reference for designing and implementing cooling systems in various hot and humid climates, facilitating energy-efficient practices and environmentally friendly building operations.

Economical efficiency of using a diesel-powered electric plant combined with an air heat pump

BACKGROUND: In settlements located in areas that do not have centralized electric and gas supply, the problems of energy supply are solved using low-power power plants based on heat engines. One of the main drawbacks of such units is the issue of fuel economy, given the cost of its delivery. In this paper, one of the ways to increase the efficiency of energy supply during the heating season in a cold climate is considered.&#x0D; AIMS: Increasing the economical efficiency of a diesel-powered electric plant with an air heat pump in conditions of low ambient teperature.&#x0D; METHODS: Simulation of operation conditions was performed in the MathCad software using the experimental data obtained at the department.&#x0D; RESULTS: Heating of outside air before entering the evaporator of the heat pump makes it possible to significantly increase the conversion coefficient and thus expand the boundaries of application of air-source heat pumps in cold climates.&#x0D; CONCLUSIONS:&#x0D; &#x0D; The combined operation of the diesel power plant with the air heat pump makes it possible to provide a single settlement with electricity as well as to supply it with thermal energy for the needs of heating and hot water supply.&#x0D; With the diesel engine efficiency equal to 37%, the unit efficiency with the heat pump increases to 57% at an ambient temperature of 15C (288 K).&#x0D; The use of air heating at the inlet to the heat pump evaporator increases the fuel use rate by 1214% due to the heat of engine and oil cooling.

Research on multi-objective optimization of control strategies and equipment parameters for a combined heating system of geothermal and solar energy in cold and arid regions based on TRNSYS

Focusing on the multiple objectives of maximum solar heating capacity, maximum COP of heat pump and minimum soil heating capacity, a model of one typical building and two heating strategies was established in the TRNSYS. Non-dominated Sorting Genetic Algorithm (NSGA) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) based on entropy weight are used to optimize operation parameters. Optimized control strategies and equipment parameters of a combined geothermal and solar system in cold and arid regions were taken as the research objects. The final optimized strategy and the original strategy of the single ground source heat pump heating system were compared. Research results show that the optimized control strategy of the geothermal solar heating system transforms solar hot water from the storage tank to heating terminals in the heating season and transforms solar hot water to the ground heat exchanger in the non-heating season. Compared to GSHP, the optimizing strategy saves 16.8 MWh annually, and the energy saving rate is 20.59%. Soil temperature drop increases from 2.74 °C to 0 °C. The annual electricity saving cost intensity is about 4 yuan/m2, and the CO2 emission reduction intensity is 4.3 kg CO2/m2. This study provides a solution for soil temperature reduction in one year and low-cost operation in cold and arid regions during ground source heat pump applications.

A regression-based approach for the explicit modeling of simultaneous heat and mass transfer of air-to-refrigerant microchannel heat exchangers

With the increasing utilization of mathematical models for heat exchanger optimization studies, there lies the demand for robust and accurate yet fast modeling methodologies on the simultaneous heat and mass transfer process. This research conducted an in-depth review of mathematical models for heat exchanger performance prediction. We categorized typical modeling methodologies into lumped models, zone models, and numerical methods. The review of mathematical models revealed the iterative approaches for performance prediction of fully wet conditions are computationally expensive. Also, the assumptions and derivations based on adiabatic fin tips do not allow flexibility with advanced fin designs. In order to address these two issues, this research developed a systematic regression approach under a common range of geometrical and thermal parameters under both wet and dry conditions, single-phase and two-phase refrigerant flow. Such regression analysis provides an explicit calculation procedure for micro-channel heat exchangers' performance prediction. The improved semi-regression models show advances in accuracy and calculation speed within the selected ranges of geometries and working conditions for heat pump applications.