Type Heat Exchanger Research Articles

기존 주택용 창문 부착형 현열교환 환기장치 제안 및 성능 평가

Purpose: Air pollution is becoming serious around the world, and indoor air quality in buildings is also deteriorating. For energy-saving ventilation and good indoor air environment, this research proposed and made a window type heat exchange ventilation system that can be installed easily in an existing house, and examined its performance. A plate type heat exchange element for ventilator was made by a 3D printer. Method: According to the Korean Industrial Standard KS B 6879:2020 Test Method for Heat Recovery Ventilator, the ventilator was tested four times in a real environment. Two experiments were measured for 10 minutes, and the remaining two were measured for 11 hours and 10 hours, respectively. Ventilation, supply air, exhaust air, and outside air dry-bulb temperatures were measured every 5 seconds. After that, the temperature exchange efficiency was calculated for ventilation, supply air, exhaust air, and outside air average temperature using the temperature exchange efficiency formula described in KS B 6879:2020. Result: The performance was 70.97% in the first experiment, 68.11% in the second experiment, 56.47% in the third experiment, and 64.16% in the fourth experiment.

CFD simulation of a shell and multiple tubes condensing heat exchanger in a modified microwave plant applied for reprocessing End of Life Tires (ELTs)

AbstractThe condensation heat exchanger has a critical role in the microwave reduction process to separate and capture valuable by‐products after the microwave reactor. This study aims to perform a computational fluid dynamics (CFD) simulation of a condenser to assess the heat transfer performance of the heat exchanger comprehensively. The type of heat exchanger used for this study is based upon an existing industrial‐scale condenser taken from a conventional thermal pyrolysis end of tires (ELT) reprocessing plant and repurposed for integration into a 1500 kg/h ELT microwave reduction process. The condenser is a shell‐and‐multiple‐tube heat exchanger in which the syngas passes through the tubes while cold water from a cooling tower is placed inside the shell. After the simulation, the effects of inlet temperatures and mass flow rates of the gas and water are investigated. The results show that the heat transfer rate is 58 kW for the inlet air velocity of 0.25 m/s and increases due to the convective heat transfer by 32% and 55% when the air velocity rises to 0.5 and 1 m/s, respectively, for the inlet gas and water temperatures of 80 and 15°C, respectively. Additionally, because the outlet air temperature and the inlet water temperature are strongly correlated with convective heat transfer, the outlet air temperature is equivalent to 17.2, 22.3, and 29.5°C when the inlet water temperature is 15, 20, and 25°C, respectively.

Modeling and techno-economic comparison of two types of coaxial with double U-tube ground heat exchangers

Among different types of ground heat exchangers (GHEs), multi-external chamber coaxial GHE is recently a promising design due to its geometrical characteristics of concentric tube-in-tube configuration and maximal heat exchange performance. Nevertheless, the characterization and commercialization of multi-external chamber coaxial GHEs need a deep understanding of the effect of different opt-geometrical and operational parameters on their thermo-economic performance. Therefore, accurate numerical modeling of the transient heat transfer proficiencies and the techno-economic feasibility of the multi-external chamber coaxial GHE and coaxial GHE compared to conventional double U-tube GHE is crucial to promise an optimal design of ground-coupled heat pump systems. This study introduces a comprehensive systematic and techno-economic analysis of the transient heat transfer characteristics of coaxial and multi-external-chamber coaxial GHEs compared to conventional double U-tube GHE. A three-dimensional numerical model was adopted and validated by field experiments. Moreover, a sensitivity analysis was conducted to investigate the impacts of several key operating and design parameters on heat transfer performance under heating and cooling modes conditions. Furthermore, various case studies, along with a comprehensive analysis of multi-objective optimization for minimization of the GHE number and energy consumption, were also carried out. In addition, a techno-economic analysis was also carried out using the total annual cost method to assess the economic viability of the proposed GHE designs. The results reveal that, compared to double U-tube GHE, coaxial GHE has the best thermal performance with maximum and average heat transfer rates of 127.54% and 17.67%, while the multi-external-chamber coaxial GHE is estimated to be 62.38% and 11.72%, respectively. Also, the corresponding total thermal resistance of coaxial GHE is the lowest by 14.86%, and for multi-external-chamber coaxial, it is 10.30%; also coaxial GHE has the lowest pressure drop by 76.45%, followed by multi-external-chamber coaxial GHE with 57.18%. In the case studies, replacing double U-tube GHE with coaxial or multi-external-chamber coaxial GHEs, the GHE number can be decreased by 13.3% for both the designs, or the energy consumption of the water pump by 33.91% and 30.97%, and the energy consumption of the entire system by 17.21% and 10.54%, respectively. The techno-economic analysis results indicate that replacing double U-tube GHE with coaxial GHE is the most feasible alternative, which can decrease the total annual cost by 13.58%, followed by multi-external-chamber coaxial GHE by 6.77%. Further discussion for the deep applications was performed, which concluded the optimal GHE design. The findings of this paper can be used as a guide for future research on GHEs for potential applications of ground-coupled heat pump systems.

A Study on the Optimization of the Louver Fin Heat Exchanger for Fuel Cell Electric Vehicle Using Genetic Algorithm

Fuel cell electric vehicles offer a short fuel charging time and high mileage, but require precise thermal management technology to ensure the durability and efficiency of the stack. Accordingly, the size and weight of the heat exchanger increase to ensure the performance of the heat exchanger. For this reason, a louver fin type heat exchanger requires optimal size and weight, as well as high performance. This paper optimally designs high-performance heat exchangers with reduced size and weight by applying genetic algorithms to solve this problem. The optimal result value was achieved by optimizing the design variables using concentrated variable modeling and a genetic algorithm, and the dynamic characteristics of the heat exchanger were analyzed by applying the driving cycle of the vehicle. In addition, 3D modeling was conducted to present the weight and practically applicable form. As a result, compared to the existing model, the heat transfer rate and effectiveness were improved by 5% and 1.6%, respectively, and the weight was also reduced by 5.8%. These results exceed the expected performance improvements of low size and weight. Moreover, it is expected that an improved heat exchanger optimization, as well as a design reflecting a drive cycle, could be conducted using the proposed genetic algorithm and be applied not only to a heat exchanger, but also to various components.

A case study on analyzing the performance of microplate heat exchanger using nanofluids at different flow rates and temperatures

A microplate heat exchanger is one of the most compact types of heat exchanger used for cooling systems, and not much research was carried out to study the performance of this type of heat exchanger with hybrid nanofluids. In this regard, the performance analysis of the microplate heat exchanger is carried out by estimating the convective heat transfer coefficient in terms of Nusselt number using a hybrid nanofluid. In current research work, Microplate heat exchangers tested using TiO2/ethylene glycol, ZnO/ethylene glycol nanofluids, and a hybrid nanofluid with varied nanoparticle volume fractions. Based on the results, it was found that the thermal conductivity of hybrid nanofluids and the overall heat transfer coefficient by applying hybrid nanofluids show better enhancement than nanofluids. The maximum thermal conductivity ratio between the hybrid nanofluid and the base fluid is 2.10. The maximum Nusselt number of 35.8 was observed for hybrid (TiO2–ZnO/ethylene glycol) at 50 °C and a volume fraction of 4%.

Significance of Darcy–Forchheimer Law, Activation Energy, and Brownian Motion of Tiny Particles on the Dynamics of Rotating MHD Micropolar Nanofluid

The time-independent performance of a micropolar nanofluid under the influence of magneto hydrodynamics and the existence of a porous medium on a stretching sheet has been investigated. Nano-sized particles were incorporated in the base fluid because of their properties such as their extraordinary heat-enhancing ability, which plays a very important role in modern nanotechnology, cooling electronic devices, various types of heat exchangers, etc. The effects of Brownian motion and thermophoresis are accounted for in this comprehensive study. Using similarity conversion, the leading equations based on conservation principles are non-dimensionalized with various parameters yielding a set of ODEs. The numerical approach boundary value problem fourth-order method (bvp4c) was implemented as listed in the MATLAB computational tool. The purpose of this examination was to study and analyze the influence of different parameters on velocity, micro-rotation, concentration, and temperature profiles. The primary and secondary velocities reduced against the higher inputs of boundary concentration, rotation, porosity, and magnetic parameters, however, the base fluid temperature distribution grows with the increasing values of these parameters. The micro-rotation distribution increased against the rising strength of the Lorentz force and a decline is reported against the growing values of the micropolar material and rotational parameters.

Study on heat transfer enhancement of nanofluid in a new type of heat exchangers

As one of the essential equipment in industrial production, improving the efficiency of heat exchangers to slow down energy consumption has become a popular topic. In this paper, the structure of a conventional fixed tube plate heat exchanger is optimized by numerical simulation, replacing the straight tube with a wavy wall tube. The impact of particle size of Cu-water nanofluid on the performance in the new heat exchanger (HEX) is also investigated. The results indicate that using the wavy wall tube enhances the flow field perturbation and improves the working mass’s flow state; adding nanoparticles in water can improve the heat transfer capacity of the fluid. It is also found that the shell process pressure drops (ΔP) and the heat transfer effect of the HEX increased with increasing of the fluid volume flow rate; at the same volume flow rate and the volume fraction of 0.5%, the ΔP of the Cu-water nanofluid in the HEX increases with increasing of the particle size. The heat transfer performance decreases gradually with increasing of the particle size. The smaller particle size of Cu nanoparticles can improve the efficiency of enhanced heat transfer to a larger extent.

Design and Optimization of Organic Rankine Cycle Based on Heat Transfer Enhancement and Novel Heat Exchanger: A Review

The effective exploitation of renewable energy and the recovery of waste heat are two crucial strategies in achieving carbon neutrality. As an efficient and reliable heat–to–power conversion technology, the organic Rankine cycle (ORC) has been recognized and accepted by academia and industry for use in solar energy, geothermal energy, biomass energy, and waste heat applications. However, there remain unsolved technical challenges related to the design and operation of the components and system. As the exergy destruction and investment cost of heat exchangers exert significant influence on the performance of ORC, investigations on the performance improvement of heat exchangers are of great significance. The aim of this paper was to provide a review on the performance improvement of ORC in relation to heat transfer enhancement, heat exchanger design optimization, and cycle construction based on a novel heat exchanger. The performance of ORC using different types of heat exchangers was discussed and the importance of revealing the influence of heat exchanger structural parameters on ORC performance was assessed. The heat transfer enhancement, novel heat exchanger investigation, and the ORC configuration development based on a novel heat exchanger were emphasized. Finally, developments and current challenges were summarized and future research trends were also identified.

Effect of the Heat Exchanger Type on Stirred Yogurt Properties Formulated at Different Total Solids and Fat Contents

In this work stirred yogurts were produced using a technical scale pilot in which the cooling step was processed using either a tubular (THX; low shear) or a plate (PHX, high shear) heat exchanger. The aim was to determine how total solids (TS, adjusted using lactose) and fat contents (FC) impact stirred yogurt properties during storage, depending on the heat exchanger used. Using raw milk, cream, skim milk powder, and lactose, four yogurts were formulated at 16.5% TS and 4.2% proteins, with different FC (0.0, 1.3, 2.6, and 3.9%); one more control yogurt was formulated at 14% TS, 4.2% proteins, and 0.0% FC. Analyses of yogurts (firmness, viscosity, induced syneresis) were realized at days 1, 3, 7, 21, and 34 after production. The addition of lactose between the non-fat yogurt at 14 or 16.5% TS had little to no effect on stirred yogurt properties. Increasing FC reduced syneresis while increasing firmness and viscosity. The use of PHX reduced the syneresis compared to THX; however, it also tended to reduce the firmness of the yogurts with 3.9% FC.

Performance Evaluation of a Heat Recovery System Combined with a Helical-Type Heat Exchanger as a Water Heater

A heat recovery system is a form of reuse of wasted heat energy as a water heater. The water heater is an effort to utilize heat from the work of the compressor without reducing the function of the air conditioner as a room cooler. This study aimed to evaluate the coefficient of performance between standard air conditioners and modified air conditioners with heat recovery systems using a helical-type heat exchanger with a distance of 0 cm between coils. This was an experimental study on a helical-type heat exchanger. Tests were carried out on standard split air conditioners and modified split air conditioners with heat exchangers. The independent variables in this study are variations of the helical type heat exchanger with a distance of 0 cm between the coil and variations in the air setting at the evaporator output. 16ºC, 20ºC and 24ºC. The dependent variable in this study is the coefficient of performance. The evaporator outlet air temperature setting of 16°C has the greatest heat recovery system value, and this is because the evaporator outlet air temperature setting of 16°C has the largest h2 value compared to other evaporator outlet air temperature settings. The greater the evaporator output air temperature setting, the greater the value of the resulting heat recovery system. In conclusion, the highest coefficient of performance is found at the evaporation exit temperature of 24ºC, and the variation in the distance between the coil is 0 cm. Meanwhile, the hottest water temperature is found in the evaporator air setting of 16ºC with a variation of the distance between the coil of 0 cm.

Evaluation of Serpentine-Type Heat Exchanger Application on Water Heater with Passages Number Variation

For some people, using warm water for bathing needs is a tertiary need because getting warm water requires additional costs. Generally, people/industry use water heaters that are sold in the market. These water heaters generally use electricity, solar power, or natural gas. This study aimed to evaluate the use of heat recovery systems as water heaters with variations in the number of passages. This research is an experimental study on a serpentine-type heat exchanger. Tests were carried out on standard split air conditioners and split air conditioners integrated with heat exchangers. The independent variables in this study were variations of the heat exchanger type serpentine with a length of 4 m, with each heat exchanger having a height of 20, 25, and 30 cm, with variations of 10, 12, and 14 passages and variations of evaporator output air settings 16ºC, 20ºC and 24ºC. The use of the evaporator outlet air temperature setting produces a different refrigeration effect value. The lower the evaporator output air temperature setting, the lower the resulting refrigeration effect value. The air temperature leaving the evaporator is 24ºC which results in a higher refrigeration effect value. This study showed the best heater performance at the evaporator air setting of 16ºC with a variation of 10 passages. In conclusion, the addition of a heat recovery system with serpentine-type heat exchanger variations 10 passages, 12 passages, 14 passages, and 24°C temperature loading variations, 20°C and 16°C on the evaporator burst will have an impact on decreasing the coefficient of performance on the split air conditioner system.

Comparative analysis of the static and dynamic dehumidification performance of metal-organic framework materials

Desiccant-coated heat exchangers (DCHEs) allow the simultaneous removal of adsorption heat and moisture from the incoming process air and support the cause of sustainability through energy recovery and energy efficiency. This study investigated the performance of a solid desiccant material namely, metal-organic framework (MOF-A520), by means of static and dynamic experimental processes. The static experiment revealed that under the same environmental conditions, the adsorption capacity of MOF-A520 is at least 12% better than the adsorption capacity of the traditional Sorbead R desiccant. Additional dynamic experiments were conducted by coating MOF-A520 on an industrial type heat exchanger within a controlled air-tunnel environment. Under the process air temperature of 30 °C, 80% RH and regeneration temperature of 80 °C, the maximum total vapor adsorption amounts (Gvap ), vapor adsorption amounts per unit contact area of fins (GA ), and vapor adsorption per unit mass of MOF-A520 (GD ) attain maximum values of 239.96 g, 0.052469 g/cm2 and 0.67596 g/g, respectively. Overall, with a lower regeneration temperature of 60 °C and shorter desorption time of 20 minutes, MOF-A520 demonstrates its potential as a suitable desiccant material for air conditioning applications.

Thin-Film Steam Generators of Binary Geothermal Power Plants

BACKGROUND: The cost of electricity generated by a geothermal power plant is twice as low as that of energy sources. However, at present, geothermal power plants mainly use submersible-type apparatus, and the most promising thin-film steam generators have not been sufficiently investigated.
 AIM: The purpose of this work is to show the advantages of a thinfilm steam generator in comparison with an immersion type heat exchanger.
 MATERIALS AND METHODS: The basis for this publication is the experimental research of the author and the analysis of data cited in the literature on heat exchange during the boiling of a film irrigating a bundle of finned pipes.
 CONCLUSIONS: The use of thin-film steam generators will significantly reduce the amount of expensive refrigerant in a geothermal power plant circuit. With a cocurrent flow of steam and liquid, the ingress of large drops onto the surface of a superheater tubes is excluded. The use of finned tubes in a bundle with optimal finning parameters ensures a uniform irrigation. The artificial centers of vaporization of the finned tube repeatedly intensify the heat transfer during film boiling, which ultimately leads to a reduction in the weight and dimensions of the superheater.

Recent Progress on High Temperature and High Pressure Heat Exchangers for Supercritical CO2 Power Generation and Conversion Systems

Heat exchangers for supercritical CO2 power generation and waste heat to power conversion systems have a significant impact on the overall cycle efficiency and system footprint. Key challenges for supercritical CO2 heat exchangers include ability to withstand high temperature and high pressure (typical temperature range of heat source 350 to 800 °C and typical required operating pressure range 150 to 300 bars), and large pressure differential between fluid streams. Other requirements are low pressure drop, high effectiveness and high reliability under thermal cycling. This paper presents recent developments in supercritical CO2 heat exchangers in terms of material selection, design, manufacture, and operation. Since heat exchangers represent a significant portion of the total system cost, another key challenge is to find a compromise between the heat exchanger type, cost, durability, and performance. This paper explores heat exchanger technologies, manufacturing techniques and materials for high temperature and high pressure heat exchangers for supercritical CO2 applications. It also identifies technology gaps and research needs to accelerate the development of effective designs to facilitate the commercialization of both supercritical CO2 heat exchanger technologies and power cycles.

COMPARING THE PERFORMANCE OF USING NANOFLUIDS IN TWO DIFFERENT TYPES OF HEAT EXCHANGERS WITH THE SAME HEAT TRANSFER AREA

Using multi-wall carbon nanotubes (MWCNTs) based on distilled water with varied volume concentrations, experimental research was conducted. The performance of two distinct heat exchangers with the same heat transfer area was assessed. A tubular heat exchanger (THE) and a shell-and-tube heat exchanger (STHE) with a heat transfer area of 20,000 mm<sup>2</sup> were employed. A tubular heat exchanger (HT31) and a shell-and-tube heat exchanger (HT33) are available from Armfield for use with the heat exchange service unit (HT30X). Three volume concentrations of nanomaterials are used to create nanofluids (0.5%, 1%, 2%). While the rate of flow was the same in the heat exchangers, the Reynolds number of the flow inside the tube ranged from 1600 to 7800 for THE and from 2500 to 12,500 for STHE due to different inside diameters. The measured variables determine the coefficient of heat transfer, friction factor, Nusselt number, and effectiveness. The heat transfer coefficient in both heat exchangers was boosted with increasing MWCNT content, according to the experimental data. Because of the nanoparticle concentration, the heat transfer coefficient of STHE is 7-43% greater than that of THE. With the increase of nanofluid concentration, the Nusselt numbers were enhanced for the two heat exchangers. The increase in the Nu number for THE is higher than in its value for STHE within a range of 28.5-40%. Correlations between the Reynolds number and MWCNT volume concentration are proposed for each heat exchanger to compute the Nusselt number and friction factor. The results of the current study have been compared with previous studies and acceptable agreement can be found.

A design model for spiral wound heat exchangers which accounts for property variation, longitudinal heat conduction, and heat-in-leak

• A combined analytical-numerical design model for cryogenic SWHE is developed. • Analytical sizing module finds the optimum configuration of SWHE. • The effects of property variation, LHC, and heat-in-leak are investigated. • LHC impact is negligible compared to property variation and heat-in-leak. • A sensitivity analysis on the input constraint is performed. Spiral Wound Heat Exchangers (SWHEs) can be a good and reliable choice for serving as the main heat exchanger in the cryogenic gas liquefaction cycles using throttling process such as the Linde-Hampson cycle. In this application, a high pressure hot gas stream has to be cooled down via transferring heat to a low pressure cold gas in a high-effectiveness heat exchanger. Present research has been organized to develop a design model which is able to find the optimum SWHE configuration for gas liquefaction cycles. The model has to be capable of considering the important physical phenomena in the cryogenic temperature ranges, including variation of fluid properties with temperature, longitudinal heat conduction (LHC) through separating walls, and heat-in-leak. Therefore, a combined analytical-numerical design model has been developed in the present study. The design model is essentially composed of two stand-alone modules, i.e. an analytical sizing module and a numerical performance evaluation module. To develop the design model, first, the geometrical characteristics of SWHE are studied and primary geometrical parameters are recognized. Then, the analytical sizing module is developed which is able to determine the optimum values of primary geometrical parameters of SWHE minimizing the heat transfer surface area based on the input design requirements. Afterwards, a 1D finite difference numerical module is presented in which important physical phenomena can be considered in the evaluation of the thermo-hydraulic performance of all types of counter flow or parallel flow heat exchangers as well as SWHEs. Finally, the two modules are combined to construct a design model. Two examples in which the low pressure superheated vapor helium is intended to cool down the high pressure supercritical helium flowing inside the tubes are also provided to demonstrate the applicability of the proposed combined model, and also, to elucidate its sensitivity to the input constraints. It was concluded that while variations of fluid properties and the external heat fluxes due to the radiation and convection have significant influence on the performance of cryogenic SWHE, the LHC is of minor importance and can be neglected. Moreover, decreasing the shell-side allowable pressure drop from 10 kPa to 2 kPa, causes the heat exchanger length and its outside diameter to increase by 79% and 48%, respectively.

Analysis of the performance of the shell and tube heat exchanger: Influence of pipe layout and diameter

Heat exchangers are devices that are used in numerous areas of industry with the most important role in process technology. The growing need for maximum energy utilization contributed to the very rapid development of these devices. Of all types of heat exchangers, shell and tube exchangers are the most widely used in process technology. The paper analyzes the performance of a shell and tube heat exchanger of known geometric characteristics and rated power. Numerically and by simulation of fluid flow in the SolidWorks software package, a comparative performance analysis was performed depending on the different layout and for the values of the outer diameter of the pipe 33,7x2 mm and 60,3x2,7 mm for the same external dimensions of the heat exchanger. The obtained results show that the heat exchanger with a circular arrangement of pipes measuring 60,2x2,7 mm has the best performance, taking into account the achieved power of the exchanger.

Long-lasting ceria-based anti-frosting surfaces

Suppressing condensation frosting using superhydrophobic surfaces can have a substantial impact on improving efficiency and safety in many industrial applications. However, the low surface energy coatings on such surfaces can be easily damaged during various harsh operations, which has limited the application potential of passive anti-frosting approaches. Here, we propose robust ceria-based anti-frosting surfaces, where superhydrophobicity is induced by not surface coating but adsorbed hydrocarbon. We also demonstrate how the incorporation of a hydrocarbon source as a binder to the ceria-based coating allows for the quick recovery of superhydrophobicity. In comparison to untreated aluminum surfaces, the developed coatings decreased the frost propagation speed and the ice adhesion strength by 60% and 89%, respectively. The coatings could maintain a low contact angle hysteresis even after 200 cycles of frosting/de-frosting robustness tests and 15,000 cycles of acidity/salinity exposure tests. Using a scalable one-step dipping process, the created coating was incorporated to a fin-tube type heat exchanger, and provided 210% enhanced heat transfer rate and 60% decreased pressure drop. The coatings also provided substantially improved robustness compared to the silane-treated superhydrophobic coating. These findings suggest that the developed ceria-based coatings can be helpful in creating scalable and resilient anti-frosting surfaces for real-world applications.

Effect of an Internal Heat Exchanger on the Performances of a Double Evaporator Ejector Refrigeration Cycle

A theoretical investigation is presented about a double evaporator ejector refrigeration cycle (DEERC). Special attention is paid to take into account the influence of the sub-cooling and superheating effects induced by an internal heat exchanger (IHX). The ejector is introduced into the baseline cycle in order to mitigate the throttling process losses and increase the compressor suction pressure. Moreover, the IHX has the structure of a concentric counter-flow type heat exchanger and is intentionally used to ensure that the fluid at the compressor inlet is vapor. To assess accurately the influence of the IHX on the DEERC performance, a mathematical model is derived in the frame of the dominant one-dimensional theory for ejectors. The model also accounts for the friction effect in the ejector mixing section. The equations of this model are solved using an Engineering Equation Solver (EES) for different fluids. These are: R134a as baseline fluid and other environment friendly refrigerants used for comparison, namely, R1234yf, R1234ze, R600, R600a, R290, R717 and R1270. The simulation results show that the DEERC with an IHX can achieve COP (the coefficient of performance) improvements from 5.2 until 10%.

Uncertainty quantification of borehole heat exchanger design length based on a global sensitivity analysis

Ground heat exchangers are essential components of ground-source heat pump systems. One of the most-used ground heat exchanger types is a borehole heat exchanger (BHE). Many parameters, such as the building thermal loads, ground thermal properties, and BHE components, influence the required BHE length. Therefore, understanding how individual parameter uncertainties are propagated to the output is counterintuitive. In this study, a global sensitivity analysis (GSA) was performed using the framework of the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) BHE design method. The GSA was conducted to identify the subparameters behind the input parameters of ASHRAE design method, which indirectly determine the BHE lengths by impacting the direct input parameters in the ASHRAE formula. The results reveal that the zone infiltration, heat pump efficiency, ground temperature, effective borehole thermal resistance, and electric equipment heat gain are the most influential parameters on the BHE design length.