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The radiant systems consume less energy and provide better thermal comfort as compared to the conventional system, but the main drawback of radiant technology is inability to cater the latent load and condensation. This problem has engaged researchers to push their emphasis on Personalized Conditioning System (PCS). It forms a micro-climate region near the occupant. This study is aimed at PCS combined with a radiant conditioning system, which evaluates the performance of the PCS and compares it with different radiant cooling systems. A radiant cubicle was used to investigate the performance of the PCS for both heating & cooling modes. For heating mode, the Standard Effective Temperature (SET) was calculated with the help of thermal comfort surveys which were in a range of 23.4°C to 27.3°C. For cooling mode, four different cases compared the performance of the system which are: Conventional Air Conditioning System (CACS), Radiant Cooled Ceiling System (RCCS), Personalized Radiant Conditioning System (PRCS), and both PRCS-RCCS coupled. It was observed that PRCS alone reaches the thermal comfort criteria with low energy consumption. The energy-saving of RCCS-PRCS was achieved 38% when compared with CACS. It can be concluded that PRCS is a new step in the field of thermal comfort.

According to the few researches on Nearly zero energy residential buildings (NZERB) in hot-summer and cold-winter zone, although it could reduce the cooling load of buildings due to its high thermal insulation and air tightness, it still needed for certain cooling in summer. This paper studied indoor environment of NZERB under three kinds of air-conditioners (split-type air-conditioner, multi-line air-conditioner and ceiling radiant air-conditioner). Firstly, a simulation model of NZERB was established based on Nanjing, a typical city in hot-summer and cold-winter zone. Secondly, variation of indoor air temperature and building load characteristics with outdoor air temperature were studied. Thirdly, indoor environment and energy consumption under three selected conventional air-conditioners in summer were simulated. Finally, the discussion was given, and an air-conditioner combining with convective and radiant cooling were proposed. The results indicated that the air-conditioner needed to be turned on in NZERB in hot-summer and cold-winter zone due to the room air temperature in off-air condition ranged from 32 °C to 36 °C, which was higher than designed indoor environment temperature in summer, but the indoor environment of NZERB under three selected conventional air-conditioners could not meet the requirements of energy saving and comfort at the same time, and a proposed convective-radiant air-conditioner could be fast, stable, and energy saving. The findings can provide a reference for conducting active technology in NZERB.

The article summarizes the results of the 25-year time horizon performance analysis of the ground source heat pump that serves as a heat source in a detached house in the climatic conditions that prevail in Wrocław, Poland. The main aim is to assess the potential of ground regeneration and reduction of CO2 emission by passive cooling application. The study adds value to similar research conducted worldwide for various conditions. The behavior of the lower source of the heat pump was simulated using EED software. The ground and borehole properties, heat pump characteristics, heating and cooling load, as well as the energy demand for domestic hot water preparation have been used as input data. Based on the brine temperatures for all analyzed cases including the ground with lower and higher values of conductivity and heat capacity, the borehole filler of inferior and superior thermal properties, and the passive cooling option turned on and off, the seasonal efficiencies of the heat pump have been calculated. The energy and emission savings calculations are based on the values obtained. The application of passive cooling reduces the brine temperature drop by 0.5 K to over 1.0 K in consecutive years in the analyzed cases and the thermal imbalance by 65.0% to 65.9%. Electric energy savings for heating and domestic hot water preparation reach 4.5%, but the greatest advantage of the system is the possibility of almost emission-free colling the living spaces which allows reducing around 33.7 GWh of electric energy and 1186–1830 kg of CO2 emission for cooling.

This research proposes the use of membrane-assisted radiant panels to improve the thermal comfort of naturally ventilated spaces in hot and humid climates. These radiant panels are capable of condi...

The cooling capacity of a radiant panel is usually measured in a certified test chamber and the value obtained is provided by manufacturers for engineers to use for in calculations. However, current measurement standards calculate the cooling capacity of a panel based on the heat carried by the circulating water, which includes the heat extraction from the plenum. Thus, sizing the radiant system based on the cooling capacity of the panels may result in an undersized system. The aim of this study was to quantify the effect of plenum temperature on the room- and plenum-side cooling of suspended radiant ceiling panels, and to develop a method to measure and predict the cooling at both sides of the panel. A cooling capacity measurement methodology with controlled room and plenum temperatures was thus proposed. The present study comprises three parts: 1) a cooling capacity measurement in a test chamber with different temperature differences between the room and plenum; 2) development of an empirical model based on the measurement data to predict the room-side cooling ratio of the panels; 3) validation of the model with dataset obtained in the field. Test chamber results revealed that an increase in the plenum temperature resulted in an increase in the measured cooling capacity but a decrease in the proportion of heat extracted from the room side. Within the tested temperature range (plenum temperature of 24–28 °C, room temperature of 26 °C), the heat extracted from the room side was 77–92% when the panels were insulated and decreased to 46–71% when they were not insulated. An empirical approach for estimating the heat extraction at both sides of the panel was then proposed. The developed model was validated through field measurements in a newly constructed office building equipped with the same panel as the ones from the chamber measurements. The predicted room-side heat extraction had an average error of 6% (with a standard deviation of 3%) compared with the measured value. The measurement and modeling procedure in this study may thus be used by manufacturers to more accurately document the cooling performance of their panels, which will enable engineers to avoid under-sizing of the cooling system.

Funding Information: The study is supported by Business Finland and the International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark . Publisher Copyright: © 2022 The Author(s) This study examines the responses of twenty-four subjects to an individually-controlled localized chilled beam (LCB) and compares it to a mixing ventilation (MV) as the reference system. Both LCB and MV also used ceiling cooling (CC) panels for background cooling (forming LCBCC and MVCC systems). The LCB directed the supply air towards the subjects to create a micro-environment around them. Four experimental conditions were established using a combination of two room temperatures (26 °C and 28 °C) and two primary ventilation rates (10 l/s and 13 l/s). During the 90 min-long experiments, the subjects were asked to assess their perceived air quality, thermal sensation, comfort, air movement acceptability and acceptability of the work environment. The results indicated that the LCBCC was superior to the MVCC with significantly higher acceptability of the work environment, perceived air quality and thermal sensation. Perceived air quality and thermal sensation were rated near the “clearly acceptable” level for both room temperatures when LCBCC was used. Moreover, thermal sensation votes were close to the “neutral” level for room temperatures as high as 26 °C and 28 °C. The micro-environment established by the LCB was found to be resilient to changes in room temperature. With the MVCC, the thermal environment was rated as “slightly warm”. No major potential risk of draught among the subjects was reported when using the LCBCC. The findings of this study contribute to the development of high-temperature cooling systems in general, and localized ventilation systems in particular.

In this paper, the thermal performance of capillary mat cooling systems is evaluated through actual measurements under different ventilation rates. The results showed that the indoor air temperature drop rates of the ceiling, wall and floor cooling are 1.42–2.44 °C/h, 0.69–1.11 °C/h, 0.29–0.58 °C/h, respectively, in the response phase, which can provide a reference for predictive control strategy of radiant system. Then the cooling capacity of the capillary mat is validated. The radiant heat transfer coefficient of the cooling capillary mat is about 5.80 W/m2 k. When the supply water temperature dropped from 20 °C to 16 °C, the total heat flux can experience an increase of 10%–30%. The heat flux for cooling ceilings is the largest, followed by cooling walls, which is 7%–17% lower; and cooling floors, which is 75%–90% lower. Orthogonal experiments illustrated that the water supply temperature and air supply volume have a significant influence on the indoor thermal environment of the hybrid systems, followed by the air supply temperature. In general, the dynamic performance of the radiant cooling system in the response phase can provide an effective reference for different control strategy considering the significant thermal inertia.

For radiant cooling to maintain equivalent comfort conditions as all-air cooling it must remove more heat from a space, the peak space heat extraction rate must be larger, and the peak must occur earlier. In this article, we assess how the magnitudes of these differences are influenced by heat gain characteristics and by the use of natural ventilation night precooling. We present measurements from a series of multi-day side-by-side comparisons of radiant cooling and all-air cooling in a pair of experimental testbed buildings, with equal heat gains, and maintained at equivalent comfort conditions. In a five-day experiment with mixed internal heat gains, solar gains, and natural ventilation night precooling, radiant cooling had to remove 35% more heat than the all-air system in equivalent circumstances; and the peak heat extraction rate was 20% larger (median difference on multiple days). In a similar experiment with highly convective internal gains the differences were smaller (26% more thermal energy, 12% larger peak), while in an experiment with highly radiant gains the differences were larger (40% more thermal energy, and 21% larger peak). The differences were much smaller in an experiment without natural ventilation night precooling (7% more thermal energy, 5% larger peak). These findings have consequences for the choice, design, and control of mechanical cooling systems, especially in buildings that also use passive cooling strategies such as natural ventilation night precooling.

Radiant cooling systems (wall and ceiling) are low exergy systems which can help in solving efficiently the comfort needs of occupants. However, a complex energy and exergy analysis should be done in the design phase of such cooling systems in order to choose the most appropriate solution. This paper attempts to present a mathematical model and methodology of such a complex analysis and illustrates through a case study the energy and exergy comparison of cooling systems with mechanical compression and absorption cooling systems. Simple relations were developed in order to evaluate rapidly the energy and exergy efficiency of these types of cooling systems taking into account the avoidance of surface condensation. It was proven that, besides the coefficient of performances of installed chillers, the temperatures in the generator and absorber, respectively the supply and return temperatures are the main influencing factors of the exergy efficiencies of such types cooling systems. Based on the developed mathematical method a numerical analysis was done assuming different operational parameters of the cooling system used in practice.

A new hybrid system for the energy cascade utilization has been proposed, integrating the hybrid ventilations, the active PV cooling, the radiative cooling together with the PCMs’ storages. A mathematical modelling together with systematic energy performance evaluation criteria has been presented to disclose the heat transfer mechanism of the hybrid system involved with different energy forms, diversified energy conversions and thermal energy storages. Multivariable parametrical analysis has been conducted and technical solutions were thereafter proposed in terms of maximizing the energy performance with the robust design and operating parameters. From our results, the interior radiant cooling system results in a stable indoor temperature with considerable energy saving potentials. The new hybrid system shows an overwhelming energy performance over the traditional system. Moreover, the polynominal fitting method is more accurate and robust than the traditional linear fitting method in terms of acquiring critical knowledge about the design and operating parameters. Research results for different scenarios with different geometrical and operational parameters have been presented to demonstrate and verify the effectiveness of the proposed technique.

Energy saving potential of radiant floor cooling combined with underfloor ventilation (RFCUV) system has been restricted by its control problems. Existing conventional control methods of radiant cooling system have several disadvantages, such as control lag, poor control performance, and low economy, etc. The objectives of this study were to: (i) build a dynamic simplified model and validate its precision experimentally; (ii) implement advanced model predictive control (MPC) on RFCUV system; and (iii) demonstrate MPC control performance by comparing with existing conventional proportional-integral-derivative (PID) experimentally. Experimental results indicated that under experimental step setpoint variations, the adjusting time of indoor air temperature or operative temperature was only 12 min with MPC controller, and was 30 min with PID controller; it took only 1 min to reach recommended thermal comfort range with MPC controller, and 17 min with PID controller. During 9:00 to 17:00 in typical design day of Nanjing city, compared with PID controller, MPC controller yielded 17.5% energy saving when maintaining equal or better indoor comfort. Thus, compared with PID, MPC demonstrated the advantages of rapid responses, good stability and excellent energy saving effect in RFCUV system.

In this paper, the cooling and dehumidifying capacities of two liquid desiccant membrane air-conditioning (M-LDAC) systems are investigated and compared when installed in an office building located in a hot-humid climate (Miami, Florida). The building HVAC system consists of a radiant cooling system to cover the sensible load and either a 2-fluid or 3-fluid M-LDAC system to meet the latent load. The systems are simulated over the warmest week of the year using TRNSYS simulation software and modelled using a previously developed analytical model for the 2-fluid M-LDAC system and empirical models for the 3-fluid M-LDAC systems. Sensitivity studies are performed where the systems are evaluated under different latent load conditions due to different occupant densities and infiltration rates. The 2-fluid and 3-fluid M-LDAC systems can meet the latent loads at lower occupant densities and infiltration rates but fail to provide thermal comfort conditions as occupancy and infiltration rates increase. It is concluded that the 3-fluid M-LDAC system uses less energy to meet the latent load than the 2-fluid M-LDAC system. The 2-fluid M-LDAC system consumes 50% more energy than the 3-fluid M-LDAC system to provide thermal comfort to the office building during the weekly simulation.

Over the last decade, building engineers have begun implementing sensible-latent de-coupled air-conditioning systems in non-residential buildings in hot-humid climates. Typically, a de-coupled system consists of a dedicated outdoor air sub-system for ventilation and high-temperature radiant cooling sub-system for space cooling. This approach has lowered cooling energy demands and fan energy consumption in buildings. However, the complete energy saving potential of de-coupled systems, specifically high-temperature space cooling sub-systems, can only be realized by using low-lift chillers that supply chilled water which matches the high-temperature radiant cooling application. This paper discusses the results of a retro-installation of a prototype modular low-lift chiller to provide high-temperature chilled water (at 17 °C) to the radiant cooling units. The paper presents temperature and cooling load profiles, control methodology and energy efficiency improvements of the low-lift cooling system. The paper also further discusses the influence of various parameters on the performance of the chiller. Despite having a cooling capacity of only 20 kW, the modular low-lift chiller is consistently able to achieve a Coefficient of Performance (COP) of 8. By operating at a low-lift (20 K) compared to a high-lift (29 K), the sensible cooling electrical consumption (at the chiller) is reduced by 23% despite being compared to a high-lift low-temperature chiller with 100 x higher cooling capacity. When normalized for cooling capacities, this reduction is between 29–30%. The project is the first known installation of low-lift cooling for building comfort control in hot-humid climates, and first reported publication of low-lift cooling in a real-life scenario - i.e., non-laboratory conditions or modelling exercise.

Thermostats control the heating, ventilation and air-conditioning (HVAC) system of a building based on the temperature they measure. Integration with communication network technologies allows wireless sensors to be used as the temperature sensing component of an HVAC system, increasing the flexibility in the selection and positioning of sensors. This study compared the temperature measuring performance of nine wireless and two conventional wired temperature sensors against reference air and globe temperature sensors in a climate chamber with a two-person office setup. The influence of sensor position, room cooling system (all-air or radiant with ventilation) and cooling load (33, 61 W/m2) was studied.Sensors placed at the same position had a measurement difference of up to 1.8 K, and assumptions about the type of temperature a sensor measures (air or globe) had the largest impact on the deviation from the reference temperatures. As opposed to common assumptions, conventional wired temperature sensors measured closer to globe temperature sensors and could be a possible indicator for the operative temperature. When the load settings were high, measurements in radiant system cases had smaller deviations from the reference sensors compared with all-air systems, due to the chilled surface compensating for the radiation from the loads.

Phase change materials (PCMs) can increase a building’s thermal mass, reducing temperature fluctuations and peaks. However, without active discharge, the PCM’s heat removal capability depends on outdoor temperature fluctuations. The present experimental study investigated the operation and performance of a novel macro-encapsulated PCM panel (MEP) with embedded pipes as an active ceiling cooling component compared to commercially available radiant cooling technologies. The results show that if the PCM was fully discharged, the installed heat storage capacity was enough to shift the cooling demand to off-peak hours. The MEP’s specific cooling power during melting was between 5.3 and 27.7 W/m2, with 11.3 W/m2 on average over the active ceiling surface for a water supply temperature and flow rate of 20 °C and 140 kg/h, respectively. Under the same conditions, the MEP performance was close to that of the radiant ceiling panels, providing a thermal environment within Category II of EN16798 for 83% of the occupied time. This is significantly better than was achieved by actively cooled gypsum panels with micro-encapsulated PCM whose pipes were in contact with them but not embedded. With its high volumetric heat storage capacity, the MEP could represent a viable thermally active building component for building refurbishment.

In the present study the performance of radiant cooling ceiling system in a room under direct solar radiation is investigated by combination of numerical and analytical solutions. Assessments are implemented in four distinct climates in Iran which include Tabriz (dry and cold), Tehran (mild and dry), Rasht (mild and humid) and Yazd (dry and hot) in the hottest hour of the hottest day of the year 2017. Efficient surface temperatures of the ceiling are determined to supply thermal comfort conditions. Turbulent flow, radiation, solar radiation is modeled by Low-Reynolds k-e model, discrete ordinate model and ray-tracing model, respectively, by FLUENT 6.3 software. To avoid condensation, critical RH method is defined to determine suitable RH accurately. Thermal comfort is investigated by PMV index. The energy saving effect of coated glass is also illustrated. Results demonstrate that by using coated glass, energy usage can be reduced 49–58%. Furthermore, changing room's orientation from west to south can boost the energy saving. Accordingly, the higher ceiling temperature which provides thermal comfort for occupants means the lower condensation probability; hence, radiant cooling ceiling systems could be utilized even in the mild and humid climate without dehumidifying necessity.

Radiant cooling system (RCS) has proven to be an energy efficient system for meeting a building's cooling requirements. RCS is energy efficient and provides better thermal comfort compared to conventional all-air heating ventilation air conditioning (HVAC) system. To further improve the efficiency of RCS, a parallel evaporative cooling system (cooling tower) is coupled with RCS and analyzed for different climatic condition using calibrated model. A statistical analysis of weather files (based on wet bulb temperature), was used to identify the availability of useful water for cooling tower integration with RCS. A comprehensive simulation feasibility study of the application of cooling tower in RCS was performed for different cities to cover every climatic zones of India. It was found that in summer, the wet bulb temperature (WBT) of different climatic zones, except warm-humid, is suitable for the integration of cooling tower with RCS. An experimental setup was designed and developed for integration of parallel chiller and cooling tower with panel-based RCS for cooling and a dedicated outdoor air system (DOAS) for dehumidification and ventilation. Experiments were conducted for chiller and cooling tower operated RCS in Composite climate of Jaipur, Rajasthan, India. Building Energy Models (BEM) were developed for both the chiller-operated RCS and cooling tower-operated RCS in EnergyPlus and calibrated with the measured data. Using the calibrated models, performance of the system was analyzed for different climatic zones of India. A chiller-operated RCS was considered as a baseline to compare the annual energy saving potential and monthly performance of the cooling tower integrated RCS. In the cooling tower–operated RCS, a total annual savings of 7% in hot and dry climates, 11% in composite climates and 20% in temperate climates was achieved compared to the chiller-operated RCS.

Radiant heating and cooling systems have significant energy-saving potential and are gaining popularity in commercial buildings. The main aim of the experimental study reported here was to characterize the behavior of radiant cooling systems in a typical office environment, including the effect of ceiling fans on stratification, the variation in comfort conditions from perimeter to core, control on operative temperature vs. air temperature and the effect of carpet on cooling capacity. The goal was to limit both the first cost and the perceived risk associated with such systems. Two types of radiant systems, the radiant ceiling panel (RCP) system and the radiant slab (RS) system, were investigated. The experiments were carried out in one of the test cells that constitute the FLEXLAB test facility at the Lawrence Berkeley National Laboratory in March and April 2016. In total, ten test cases (five for RCP and five for RS) were performed, covering a range of operational conditions. In cooling mode, the air temperature stratification is relatively small in the RCP, with a maximum value of 1.6 K. The observed stratification effect was significantly greater in the RS, twice as much as that in the RCP. The maximum increase in dry bulb temperature in the perimeter zone due to solar radiation was 1.2 K for RCP and 0.9 K for RS – too small to have a significant impact on thermal comfort. The use of ceiling fans was able to reduce any excess stratification and provide better indoor comfort, if required. The use of thin carpet requires a 1 K lower supply chilled water temperature to compensate for the added thermal resistance, somewhat reducing the opportunities for water-side free cooling and increasing the risk of condensation. In both systems, the difference between the room operative temperature and the room air temperature is small when the cooling loads are met by the radiant systems. This makes it possible to use the air temperature to control the radiant systems in lieu of the operative temperature, reducing both first cost and maintenance costs.

A conventional radiant panel system offers advantages in terms of energy savings; however, compared with an all-air system, it has limitations such as moisture condensation risk, slow air movement, difficult space zoning, slow air pollutants removal from a highly polluted room, and time delay in start-up of the radiant panel system. This research performs an energy consumption analysis of a hybrid radiant cooling system for buildings in summer. The hybrid radiant cooling system combines a typical radiant panel with a decentralized air convector connected in series. The hybrid radiant panel system generates additional cooling output through its air convector, dehumidifies indoor air, increases indoor air movements, and reduces the time delay in start-up and a filter in the air convector removes air pollutants. This study exhibits the energy performance of the hybrid radiant cooling system compared with an all air system and a typical radiant panel system via numerical modeling using experimental data. This hybrid radiant panel system is effective for energy-saving, because it has a higher cooling impact ratio, and larger coefficient of performance of the chiller, and because the air movement increases the offset effect of the operation indoor temperature rise by an enhanced mixed convection effect. Thus it can reduce cooling energy consumption. The hybrid radiant cooling system can be used very effectively for saving energy in the summer season.

The objective of this study is to investigate the energy saving potential of a dedicated outdoor air system (DOAS) with a thermoelectric module radiant cooling panel (TEM-RCP) by comparing it with those of both a conventional variable air volume (VAV) system and a DOAS with hydraulic ceiling radiant cooling panels (CRCP) via a detailed energy simulation. The theoretical and empirical models for each component were used to estimate the energy performance of a VAV system and a DOAS with CRCP. Additionally, the TEM-RCP was analyzed by using the developed simulation models based on the semi-black box model. Hourly simulations were conducted to measure the annual energy performance. The results indicated that the DOAS with a TEM-RCP consumed 40.7% less operating energy annually when compared with that of the conventional VAV system while the proposed system exhibited only 1.0% more annual energy consumption when compared with the DOAS with hydraulic CRCP given the relatively low dimensionless figure of merit (ZT) of the TEMs (i.e., 0.73) that is used in the TEM-RCP. However, the average coefficient of performance (COP) of the TEM-RCP for cooling was 8.3, which is significantly higher than that of the conventional CRCP (4.6) during the operation period. This is because the TEM-RCP uses a cooling tower for heat removal, and its cooling water temperature is sufficiently low without requiring additional cooling of the TEM except during summer. Therefore, TEM maintains radiant panel temperature with low electric energy consumption. The study also indicated that if the ZT value of TEMs exceeded 0.75, then the proposed system exhibited lower annual energy consumption when compared to that of the DOAS with CRCP.

Convection-radiation combined cooling systems are commonly used in residential buildings in hot summer and cold winter areas because of their high thermal comfort. When this system is used in office buildings, combined with the characteristics of office building’s working time occupancy patterns and building typologies, the operation strategy can lead to different energy consumption under the same thermal comfort. In this study, three operation strategies are compared to a system that combines two different terminal units in the same thermal zone: a radiant floor and fan coil. The performance of the combined system is assessed in terms of the thermal comfort level, hourly refrigeration performance coefficient, and energy consumption. The results indicate that the system with an intermittent operation strategy reduces energy consumption by approximately 39% compared with a continuous operation strategy, with little impact on thermal comfort. The room temperature under the three control strategies meets the temperature requirements of the office building during working hours. The fluctuation in room temperature is smaller under the continuous operation strategy than under the intermittent operation strategy, which indicates that the thermal environment of the room has better stability during continuous operation. The maximum indoor vertical gradient is always less than 3 °C, which meets the ASHRAE55-2017 standard. The room-temperature fluctuations are strongly affected by solar radiation. Therefore, building shading measures should be considered in building designs to avoid local discomfort or energy waste. When the system operates stably, the Predicted Mean Vote (PMV) value is low. The reason for this is that the radiant cooling system reduces the average radiant temperature of the building to adjust the room temperature. Therefore, it is recommended that the indoor design temperature of the radiant cooling system be increased by 2–3 °C to ensure better indoor comfort.

Radiant cooling systems need optimized control strategies to provide superior comfort while maximizing energy-savings. The field measurement method was used to study the operational control of radiant floor cooling (RFC) with a direct-ground cooling source and displacement ventilation (DV) systems. The control methods for the composite system were proposed based on three factors including floor surface temperature relative to the indoor air dew point temperature, the range of indoor/outdoor air temperature and humidity, and the indoor thermal and humidity loads to be countered. These factors were considered in three typical scenarios: intermittent operation, variable initial temperature and humidity conditions, and sudden increases in indoor heat gain, so that maintaining the operative temperature within 26–27 °C. The system required that precooling time of the RFC was 2.5–3 times the time to achieve 63% of the temperature change for intermittent operation on weekends, while the DV system was started 1–1.5 h before work time when initial indoor air humidity was higher than 75% and indoor air temperature was higher than 26 °C, and supply air flow rate was increased to maximum value under sudden increases in indoor heat gain. The results concluded that dynamic optimal control of the radiant cooling system was achieved.

Radiant cooling systems have become increasingly prevalent due to their great potential in comfort and energy saving. Nevertheless, their applications are limited by condensation and slow response. This study aims to explore the intermittent operation characteristics of radiant cooling systems and propose an effective operation strategy to improve system reliability. An operation strategy called standby cooling was proposed, and a none standby cooling scheme and four standby cooling schemes were simulated with the transient system simulation tool (TRNSYS). The results show that the none standby cooling scheme was difficult to satisfy the indoor comfort of the rooms with long shutdown periods. The indoor dry-bulb temperature and dew-point temperature when the air-conditioning mode is turned on have the approximate monotonic relationships with the maximum predicted mean vote (PMV) during the occupied period, and the Spearman correlation coefficient were 0.8809 and 0.8019, respectively. By contrast, with increased energy consumption, the standby cooling schemes can satisfy the comfort well and ensure the smooth operation of the radiant cooling system. With the same radiant system setting, the extra energy consumption of the schemes with continuous fresh air supply is 67.71%∼157.42% more than that of schemes that supply fresh air intermittently. With the same fresh air system setting, the schemes turning off the radiant cooling system need 11.67%∼71.41% more extra energy consumption than the schemes turning on the radiant system. Accordingly, from the perspective of energy consumption, one should turn off the fresh air system and turn on the radiant system as much as possible. This study provides a theoretical basis for understanding intermittent operation characteristics of radiant cooling systems and can direct the design and operation to enhance system reliability with less energy consumption.

Solar heat gain is an important part of the cooling load of a building, especially for a radiant cooling room. This study presents the development of a mathematical model based on the state–space method, which can consider the influence of dynamic solar heat gain on radiant cooling floor. The calculated results were consistent with the experimental data. The maximum relative error of each calculation time node of envelope and indoor air were within 7%, and that of floor surface temperature was 12.75%. Base on the model, the dynamic cooling performance of radiant floor under various conditions such as different filling layer thickness, building orientations, shading forms and operational modes were investigated. The results demonstrated that the intensity and time distribution of solar radiation exerted significant effects on the intermittent operational characteristics. Furthermore, the optimal selection of the radiant floor filler layer should be considered with operation mode. For the normal operation mode, the cooling performance of the floor with 50 mm filling layer was better than that of the floor with 100 mm filling layer. With regard to the pre-cooling mode, the cooling performance of the floor with 100 mm filling layer was excellent. The model can provide guidance for the design and operation of radiant cooling floor in different practical situations.

This paper investigated thermal comfort of radiant cooling with subjects who are accustomed to a tropical hot humid climate. Thermal sensation, thermal acceptability, and thermal preference were assessed from observations of a large group of the subjects in a radiant cooling experimental room refurbished as an office-like environment. The analysis results showed that the operative temperature for the thermal neutrality was about 25.0 °C, and the acceptable temperature ranged from 22.5 °C to 26.5 °C. Air movement played a key factor influencing on the subject preference in the radiant cooling, while the room relative humidity had less significance. In this study, a field comfort survey of the conventional mixed-air system was also carried out in real occupied spaces by using the same questionnaire and measuring devices from the radiant comfort experiments. The comparison showed that the thermal responses of the subjects were different between the two air-conditioning systems.

One of the factors that limit the cooling capacities and application potentials of radiant cooling panels is the condensation risk. The self-condensate-repellency tendency of superhydrophobic surface materials provides a possibility to mitigate the condensation risk. This paper studied the size ranges of condensate drops formed on a superhydrophobic aluminum sheet of the size 25 mm × 25 mm attached to a cooled ceiling panel in a climate chamber in the humidity range between 50% and 80% and at the temperature of 25 °C and air change rates from 0 ACH to 9 ACH. Using an optical magnifier, large drops up to the size 802.5 µm were observed in certain fixed positions in the large view area of 4.08 mm × 3.06 mm under different experimental conditions; whereas in a smaller focused view area of 0.96 mm × 0.72 mm the diameters of the largest drops were found to first increase over time and then reached around 80 µm with occasional size of 152 µm. All these were in contrast with the continuously growing drops simultaneously observed on the ordinary aluminum sheet, which reached 4 mm. The largest size of the droplets in the small focused area increased from 54.1 µm to 151.7 µm as humidity increases from 50% to 80%, but did not change much as the air change rate changed from 0 ACH to 9 ACH. This series of experiments confirm our hypothesis that condensate drop sizes can be limited within the un-perceivable range, namely below the sensory and visual thresholds, in typical indoor conditions because of the droplet jumping mechanism that occurs on the nano-engineered superhydrophobic surface, but it remains to be ascertained whether the large condensate drops formed at certain fixed points in the other parts of the tested nanostructured surface were associated with some defects in the nano-scale, and whether this can be eliminated on a larger area of practical application scale.

A decoupled radiant cooling unit (DRCU), which uses an infrared-transparent and conductive resistant (ItCr) layer to cover the radiant cooling surface and prevent it from contacting with air, reduces the condensation risk and simultaneously increases the cooling capacity. The cooling capacity could be enhanced using a low radiant cooling temperature (e.g.

This study aims to evaluate thermal performance of a new ventilated Trombe wall integrated with phase change materials (PCMs-VTW). Double PCM wallboards are embedded in the building facade for different purposes, i.e. exterior PCM wallboard is to store natural cooling energy via night-time ventilation, and interior active PCM wallboard is for radiant cooling. Melting temperature and latent heat of PCM have been discussed for PCMs-VTW system from 1st August to 7th August in Changsha, China. Also, high-reflective coating is coated on the exterior PCM wallboard for reflecting solar radiation, thus ameliorating daytime overheating. Nighttime ventilation is for natural cooling energy storage via regenerating solid exterior PCM wallboard. The obtained result shows that under the weather condition in Changsha, melting temperature 22 °C for interior PCM and the latent heat 176 kJ/kg for exterior PCM show considerable benefit for cooling energy release. Compared with the classical Trombe wall system, annual cooling energy consumption is decreased by 20.8% and by 18.6% in the PCMs-VTW system when indoor air temperature is kept at 22 °C and 24 °C respectively. Our research has provided scientific evidences for potentials provided by PCMs-VTW system in reducing building energy consumption and improving indoor thermal comfort via exploiting natural cooling energy, mitigating overheating at summer condition and utilizing cold sources in high temperature.

Direct expansion (DX) dedicated outdoor air system is shown to be a cost-effective energy efficient complement to ductless variable refrigerant flow and radiant cooling systems by providing conditioned ventilation air at the required set point temperature and relative humidity in an energy efficient manner. We compare five balanced flow dedicated outdoor air system configurations under typical office/lab ventilation loads coupled to an air-cooled outdoor unit for 24 Gulf Cooperation Council (GCC) locations representing GCC climates. All configurations use an enthalpy recovery wheel (ERW) to remove heat and moisture from intake air—before it reaches the active DX dehumidification element—by passive heat and mass transfer to the exhaust stream. It is found that of two run-around heat exchanger configurations, using a rotary heat wheel across the evaporator is a more efficient configuration than placing the heat wheel (HW) between the supply and return air streams. Furthermore, adding a subcooling coil for reheat in parallel to the HW results in higher efficiency than adding the coil in series with the HW. The Life cycle cost optimized ERW and HW effectiveness for the configuration with HW between supply and return air was found to be 0.86 while the ranges for run-around HW configurations with subcooling/reheat were found to be 0.8–0.85 for ERW and 0.74-0.82 for HW in GCC climates with significant dehumidification loads. Thus, the evaporator run-around HW reduces the volume, mass and cost of the DOAS unit while providing higher overall efficiency.

Radiant cooling is a promising thermal control technology for built environment. Unfortunately, condensation limits the potential of radiant cooling. Recently, numerous technologies have been developed to address the issue of condensation on radiant cooling surfaces. Nevertheless, a special review on the condensation control for radiant cooling is absent. The passive condensation prevention for radiant cooling refers to a technology that could realize the dew-free operation of radiant cooling terminals without additional control strategies or external energy consumption. The methods of creating surperhydrophobic surfaces and adding cover shields to prevent condensation on radiant cooling surfaces are systematically reviewed, involving anti-condensation mechanisms and specific studies. Finally, the limitations of passive methods are critically discussed and perspectives are proposed, attempting to seek suitable solutions and inspire new ideas for future research. In this study, the concept of passive condensation prevention for radiant cooling is proposed for the first time. It is aimed to release the potential of radiant cooling and provide alternative ideas for the design and application of radiant cooling.

Sleeping pods are special confined enclosures used as quiet spaces for short naps (e.g., in libraries and airports) or as cheap accommodations in metropolitan cities. This study aims to analyze the thermal environment in such pods when operating with radiant cooling panels, as potential energy saving (high-temperature cooling) systems, using a validated computational model. The results show that the pod can be maintained at category A (predicted percent dissatisfied of nearly 5%) by maintaining a high supply air temperature (25 °C), a relatively high panel temperature (19 °C), and using an untreated panel surface (emissivity of 0.7). Most of the considered operational settings showed no signs of local thermal discomfort, where the draft risk is below 10%, the radiant temperature asymmetry is lower than 10 °C, and all pod surfaces are safely touchable. Besides, no condensation risks are encountered. The cooling capacity of the panel ranges between 24.4 and 65.65 W/m2 and the radiation heat share ranges between 23.2 and 41.0%. The cooling capacity was found to increase by decreasing the panel’s temperature, increasing the panel’s emissivity, and increasing the supply air temperature. When switched on, the internal heat dissipation appliances increased the operative temperature by 2.6%, decreased the draft risk by 11.6%, and increased the cooling capacity by 13.9%, but the pod’s environment only moved from category A to the beginning of category B.

Radiant cooling/heating (RCH) panel systems have recently received increasing attention because of their energy-efficient operation and improved comfort performance. Therefore, this study proposes a novel RCH panel with segmented concave surfaces . The new panel has the same surface area as a conventional flat surface panel. A series of laboratory tests were conducted to investigate the heat transfer characteristics inside a chamber equipped with the new panel. Moreover, a three-dimensional finite volume simulation was developed to investigate the heat transfer, fluid flow, and thermal comfort conditions inside a single room equipped with the proposed panel, and the results were compared with those of a conventional flat surface panel under the same operating conditions and cooling load. First, the curvature cord length ratio to curvature radius ( L/R) was optimized in the range of 0 (flat) to 2. In all cases, the surface area was the same, but the coverage area ratio varied. In addition, the impact of different coverage area ratios from 55% to 81% and the influence of adding void spaces of 29 mm and 11 mm between adjacent curved segments were analyzed. The results showed that the simulation achieved good agreement with the experimental results with an accuracy of 98.9%. The coverage area ratio played an essential role in decreasing the indoor air temperature by 2 °C and reducing the floor temperature by 1.6 °C. When the L/R ratio changed from 0 to 1.5 at a coverage ratio of 81%, the average air temperature decreased by 1 °C. Moreover, increasing the L/R ratio from 0 to 2 with void spaces of 2.9 mm and 11 mm reduced the radiation heat transfer coefficient , hr , by 31%, while the convection heat transfer coefficient , hc, at the panel upper surface increased by 174%. Changing only the panel surface shape from flat to concave and segmented enhanced the thermal performance and thermal comfort inside the indoor environment.

The consequences of global warming and urban heat islands have led, amongst other things, to a rapid increase in cooling-related energy use and environmental emissions. Given the serious implications of this development, concerted efforts are needed in view of required new strategies. In this context, the present contribution focuses on an alternative user-centric radiant cooling solution. Conventional radiant cooling systems have been promoted in view of their energy efficiency potential, as well as enhanced thermal comfort provision, due to a draft-free cooling process. However, condensation risk can limit the application scope of these conventional systems. The alternative user-centric strategy is intended to address this limitation by positioning vertical radiant panels closer to occupants and incorporating drainage systems for potential surface condensation. A preliminary laboratory study was conducted to gain a first impression of the performance of user-centric vertical radiant panels. To this end, radiant panels were installed and operated in two test rooms. A small group of participants subjectively evaluated thermal comfort under different ambient air and panel surface temperatures. The results point to both the potential and the limitations of the proposed user-centric radiant cooling solution.

The Thermoheliodome is an experimental pavilion that explores cooling without air conditioning. The two research aims were to explore the use of indirect evaporative cooling and the geometric reflection of radiant cooling. For evaporative cooling we utilize a cooling tower outside of the pavilion to indirectly supply water chilled near the wet-bulb temperature. The radiant cooling system is made up of 55 coaxial chilled pipes each located in the central axis of cones with reflective surfaces that spectrally reflect the surface of the pipes and expand their radiant view factor to the occupants inside the pavilion. The specific geometry was digitally fabricated using an industrial robot and hot-wire foam cutter. The mean radiant temperature (MRT) was shown to be significantly decreased using thermal imaging cameras and with a novel scanning MRT sensor. The radiant cooling delivered from the fluid is maximized by reflection and concentration of heat emitted by occupants on the pipes, while the convective cooling of the air is minimized because only the small pipes are cooled and the reflecting surfaces are not, so the convective heat transfer surface area is small. Under typical indoor office conditions the ratio of radiant to convective cooling is slightly greater than one. For the Thermoheliodome the radiant ratio was greater than 10. Occupant surveys found that although the air temperature was not modified, they felt that inside the space there is a cooling sensation ( p ≤ 0.01). The day of the survey they felt on average 3 °C cooler.

Building integrated photovoltaic thermoelectric (BIPVTE) wall system is highly energy efficient and self-adaptive to the environment. This sophisticated system is supported by the co-work of PV module for solar radiation transformation, air gap for thermal dissipation and thermoelectric radiant panel system (TERP) for active radiant cooling/heating. The purpose of this study is to develop an accurate and fast simulation method of this complex system which could be beneficial for system design, control and optimization for application. The present study upgraded the PV model by considering the variable resistance due to Peltier Effect in thermoelectric module. A new non-uniform time step model was proposed which can provide an improved and more efficient system simulation. The non-uniform time step solution of BIPVTE system was validated by comparing with both uniform time step solution and experimental data. The parametric studies on time step h and superposition number N under uniform time step solution, as well as two linear deviation coefficients d T and d G under non-uniform time step solution, were respectively analyzed. In uniform time step solution, the simulation time step h and parameter N should be properly chosen to balance simulation speed and accuracy. However, in non-uniform time step, numerical investigations demonstrated that simulation accuracy can be kept within an acceptable range even when linear deviation coefficients were large enough. The algorithm can be further accelerated by adopting Gauss-Berntsen-Espelid or Gauess-Kronrod rule in numerical integral calculation. The comparative and case study in this research has shown the validity and robustness of the proposed non-uniform time step model, which could be a useful tool for further work on BIPVTE as well as other building systems.

The thermal environment in a double office room obtained with chilled beam (CB), chilled beam with radiant panel (CBR), chilled ceiling with ceiling installed mixing ventilation (CCMV) and overhead mixing total volume ventilation (MTVV) under summer (cooling) condition was compared. Design (peak) and usual (average) heat load from solar radiation, office equipment, lighting and occupants was simulated, respectively at 62 W/m2 and 38 W/m2 under four different workstation layouts. Air temperature, globe (operative) temperature, radiant asymmetry, air velocity and turbulent intensity were measured and draught rate was calculated. Manikin-based equivalent temperature (MBET) was determined by using two thermal manikins. CCMV provided slightly more uniform thermal environment and the least sensitive to different workstation layouts than the other systems. CB provided a bit higher draught rate levels than CCMV especially in the design heat load cases. With CBR, the thermal environment was found to be between CB and CCMV. MTVV generated high draught level under the tested design heat load cases. All cooling systems generated similar thermal environment in the usual heat load cases. It would be recommended to include the measurement height of 0.05 m in indoor climate testing standards for obtaining more generic view of the draught risk.

Radiant cooling systems are currently used in many parts of the world. However, the relatively long thermal response time of such a system causes numerous concerns regarding their operation. This study emphasizes the operation dynamic of radiant systems through on-site measurement and simulation. The results of on-site measurement imply that the capacity of heat extraction at a cooling surface can be improved by altering the operational strategy of the radiant system based on Beijing weather. The feasibility in a typical office building with a same radiant system can be studied by simulation. The results show that 9–15% of cooling energy is required during the occupied period that can be conserved in the thermal mass in advance, and the peak sensible cooling loads of terminal devices decrease at 32–39% compared with that in the conventional scheduling. Although the altered operation strategies lead to increased cooling demands, the electricity consumption and costs decrease because of the improved coefficient of performance and low electricity tariffs at night. The convectional strategy is still recommend for the radiant system with less thermal mass because the indoor environment can be controlled precisely.

Green roofs have been proposed for energy saving purposes in many countries with different climatic conditions. However, the energy saving potential of green roofs depends on several aspects, such as the climate characteristics or the building loads. For this reason, the authors have been working on ways to modify the thermodynamic behavior of green roofs through passive low energy systems operating according to rules based on the relationships between the indoor and outdoor temperatures. This paper discusses the improvements in indoor thermal comfort which can be obtained by adopting water-to-air heat exchangers and indirect evaporative and radiant cooling strategies in buildings with green roofs. The study specifically looks at the effect of combining a simple evaporative/radiant system that cools the water pond where the water-to-air heat exchange occurs. Ad-hoc built test cells were investigated in southern California for over a year. Overall, the water-to-air heat exchangers proved to cool the indoor air in the test cells by almost 10 °C when the exterior temperatures were above 35 °C. In this system, the heat from the interior of the cells that could not be absorbed by the green roof, was transferred to the coupled water sink, and then dissipated into the atmosphere. This study shows that the benefits of the water-to-air heat exchange and of the evaporative cooling system are promising, while the water consumption is limited. Finally, the experimental investigation summarizes the benefits of combining green roofs and evaporative and radiant cooling of a water-to-air heat exchanger as a solution for building cooling and proposes simple equations to anticipate their temperature cooling effects.

This study aims to investigate the effect of using cooling ceiling and desk fans on comfort in hot-humid environment. A series of experiments was conducted in an experimental room at 26, 28 and 30 °C (relative humidity was 70%). The obtained results indicate that the combination of cooling ceiling and desk fans reduced warm sensation and improved comfort in hot-humid environment, which mainly resulted from the improvement of local conditions of upper body parts. This combination also lowered humid sensation and improved perceived air quality but the local airflow by desk fans caused draft risk at 26 °C. Besides, cooling ceiling could only meet the 80% acceptable demand at 28 °C, while cooling ceiling and desk fans made more than 80% subjects feel acceptable at 28 and 30 °C. Also, the combination exerted more significant effects on increasing acceptability to both humid environment and air quality than using cooling ceiling alone. Besides, the preferences of subjects for cooler environment, stronger air movement and drier environment were significantly weakened under hot-humid conditions. In addition, the combination had potentials of energy conservation since it could extend acceptable range and reduce the energy for dehumidifying indoor air.

The current article describes a case study that estimates the energy-saving potential of radiant cooling systems in different climate zones of India using calibrated building energy simulation. The...

This study investigated the cooling potential of a green roof paired with a radiant cooling system in a hot and dry environment in southern California. The green roof had pipes embedded in it which were connected to a radiator inside the test cell. The radiator absorbs heat from the interior of the cells which is dissipated through the green roof and the evaporative cooling that occurs during the irrigation process. Excess water that is not absorbed is recollected and reused. Experiments demonstrate the potential for a system such as this one that combines water based cooling and green roofs, demonstrating to improve thermal comfort and reduce energy consumption. The test cell with the green roof and radiant cooling system was monitored and compared with other cells in over 40 tests conducted over the summers of 2015 and 2016. The results demonstrated that this test cell maintained lower indoor temperatures than the other test cells, including other cells with green roofs. The best performance occurred when the radiant system pump was operating continuously, with the irrigation sprinkler working 20 min per hour from 11:30 a.m. to 4:30 p.m. An equation to predict indoor maximum temperature as a function of the daily temperature swing was derived.

This study aims to investigate thermal comfort of subjects with a new type of radiant cooling desk in hot environment. A series of experiments was conducted in an experimental room at 28, 30 and 32 °C in summer. Totally, 20 subjects (10 males and 10 females) participated in the experiments. During the test, subjective responses and some parameters of radiant cooling desk were recorded. The obtained results indicate that radiant cooling desk reduced warm sensation and increased both comfort and acceptability of subjects in hot environment, while it weakened the preference for cooler environment. Radiant cooling desk mainly cooled upper body parts and this effect was more significant in warmer environment. Besides, subjects were free from draft risk but they still wanted higher velocity in hot environment. In addition, the surface temperature of radiant panels at 28, 30 and 32 °C were 22.8, 23.9 and 25.5 °C respectively, which lowered condensation risk. And the cooling capacity of radiant cooling desk at 28, 30 and 32 °C were 89.9, 104.4 and 130.7 W, respectively. Since radiant cooling desk can extend acceptable temperature range and use high-temperature supply water, it has large potential for energy conservation.

Night sky radiant cooling is one of such promising natural techniques that can be worth a high recommendation. In this study, a novel design of night sky radiation heat exchanger is proposed, and i...

Densely occupied spaces such as classrooms can very often have problems with overheating. It can be difficult to cool such spaces by means of a ventilation system without creating draughts and causing discomfort for occupants. The use of a wall radiant cooling system is a suitable option for spaces with a high occupant density. Radiant systems can remove most sensible heat loads resulting in a relatively small requirement for supply air for ventilation.

In this paper, a mathematical model for predicting the departure duration of the first condensate droplet from a radiant ceiling surface was proposed on the basis of the condensation water mass. The simulation results indicate a dependence of condensation water mass on the apparent contact angle of the substrate, but almost in no relation with the surface temperature. The condensation water mass firstly increases with the increase of the apparent contact angle. It reaches a maximum weight of 522 g/m 2 at an apparent contact angle of 110°, and then decreases. A visualization experiment of condensation on a radiant ceiling panel with a conventional aluminum alloy surface was performed in a climate chamber to measure the departure duration of the droplet. The measured departure duration fluctuates due to the variance of apparent contact angle and the randomness of condensation process, but it decreases sharply with the sub-cooled degree (air dew point minus surface temperature). And the average departure duration is 10 h with a sub-cooled degree of 5 °C. The theoretical model is validated as the average relative biases between the experimental and theoretical results are within 25%.

The energy-efficiency aspects and cost-saving features of various radiant cooling systems have been reported in many previous studies. However, the available literature on the analysis of initial investment and maintenance costs is scanty, especially for the slab-integrated one. A field survey was carried out in a green building in Malaysia that was installed with a combined radiant-convective system. The performance of this multi-floor radiant slab cooling system was studied and the energy conservation potential was evaluated by comparing the data obtained from the building energy management system (BEMS) with the estimated energy consumption of a conventional convective air system. Also, price quotations and service maintenance contracts were obtained for a complete cost-benefit evaluation of both systems. It was found that the radiant slab cooling system was able to reduce 34% of the energy consumption compared to the conventional variable air volume system while providing the same level of air conditioning. Despite its higher initial cost, the payback period for the investment cost is about 2.5 years. These findings are particularly useful for design engineers in the tropics to consider an alternative cooling technology for large office buildings which is more energy efficient and cost effective.

Radiant cooling systems are a subject of increasing scientific interest due to their efficiency and ability to use high-temperature cooling sources. In hot and humid conditions, they have generally been studied in combination with dehumidification systems. For retrofit projects, a control system that would eliminate the need for dehu-midification would be beneficial. In the present study, a passive geothermal-based radiant high-temperature cooling system is studied in a Mediterranean climate. The system is operated with supply water temperature control using dew point temperature as a controlling variable. The system’s performance is compared with that of an all-air cooling system. The systems are evaluated using IDA-ICE building energy simulations, validated with on-site measurement data. The results show that the radiant cooling system produces the same level of thermal comfort with 40% lower energy use and 85% lower exergy consumption than the all-air system. The risk of condensation limits the cooling capacity of the radiant cooling system. Consequently, insufficient cooling ca-pacity causes thermal discomfort for the occupants due to the operative temperature exceeding 26 ◦C. QC 20201130 GEOFIT

With increasing demand for building energy savings and comfort, radiant cooling systems have received increasing research attention, and novel radiant cooling terminals have been developed in recent years. However, poor surface temperature uniformity and the issue of coupled condensation prevention and cooling capacity remain the two major limitations of radiant cooling terminals. In this study, a novel radiant cooling terminal integrated with a heat exchanger and a flat heat pipe was developed. A novel cooling mode was proposed by using the flat heat pipe for sensible heat transfer only and the heat exchanger for both cooling and dehumidification. Furthermore, forced convection was added to the terminal to further optimize the cooling performance. Heat transfer analysis and thermal performance of the terminal were conducted. The novel terminal has advantages in thermal response speed (360–535 s) and surface temperature uniformity (±2 °C) due to phase change. The sensible and latent heat transfers were separated. The dehumidification-adjustable cooling method changed the cooling capacity of the terminal from 104.4 to 357.4 W, and the proportion of latent heat transfer varied between 12.1% and 26.4%, with preliminary results showing decoupled condensation prevention and cooling capacity improvement. Furthermore, adding forced convection increased this decoupling, and the surface temperature and cooling capacity simultaneously increased by 4°C-6°C and 75.7%, respectively. Cooling terminal performance improved owing to the dehumidification-adjustable cooling method, which had a referable application value.