Comfort Temperature Range Research Articles

Energy Consumption Patterns and Characteristics of College Dormitory Buildings Based on Unsupervised Data Mining Method

The college building is a large energy consumer with a high density of energy consumption. However, less attention is paid to college buildings, particularly college dormitory buildings. Based on the one-year historical data collected from 20 college dormitory buildings located in Wuhan, China, this study aims to propose a three-stage strategy to identify and analyze the energy consumption patterns and characteristics of college dormitories in detail, including determining energy consumption patterns, analyzing key characteristics based on four indexes, and examining three influencing factors (occupants’ gender and floor and orientation location of rooms). The results show that the heavy energy users (around 10% of all occupants) consume around 20% of the total energy and have the narrowest comfort temperature range. However, the light energy users, 42% of total occupants, consume only approximately 27% of total energy. Their different tolerance to coldness is the main reason contributing to different energy consumption. The dormitories of males and location of the top floor and corner tend to consume significantly more energy in hot weather. This study would help campus facilities to understand the energy use behavior of occupants and formulate adequate policies so as to improve the energy management of campuses.

Energy-Constrained Indoor Air Quality Optimization for HVAC System in Smart Building

The heating, ventilation, air conditioning (HVAC) system is a common ventilation system applied to an indoor environment based on Internet of Things (IoT) technology. In HVAC, providing a comfortable temperature under the constraint of energy is a major challenge. In this article, we propose an air quality optimization strategy to control the air supply and energy consumption, and build several dynamic models to capture the stochastic processes in HVAC. Besides, a system utility maximization problem is formulated. We provide a solution framework based on the Lyapunov optimization method. Based on this framework, we propose a utility-optimal air quality optimization algorithm to solve the subproblem, and theoretically prove that it can achieve the near-optimal system utility. Additionally, the upper bound of the indoor temperature is derived, and the optimality of the algorithm is analyzed. Simulation results show the impact of the system parameter on the HVAC system and the indoor temperature, and verify that the proposed strategy and methods can maintain the comfortable temperature range and supply more fresh air effectively under the constraints of energy consumption.

Roadmap to reduce the direct effects of climate change on building performance; A case study applied to the top 8 deserts and top 8 coldest regions in the world

Climate change significantly impacts building performance. Indoor comfort, energy demand, carbon emissions, and building maintenance costs vary according to the local climate. This research has been conducted, to investigate, simulate, analyze, compare and discuss the potential impact of climate change on thermal comfort, heating and cooling energy needs in a hospital, hotel, school and residential home located in the top 8 deserts and the top 8 coldest regions in the world. Simulations were conducted for future climate using ten (10) general circulation models (GCM) based on three emission scenarios, namely B1(low emission), A1B (middle emission), and A2 (high emission); and Representative Concentration Pathway (RCP) (RCP2.6; RCP 4.5, and RCP 8.5). The thermal performance of buildings was assessed for three periods (Current, 2050 and 2100). The results showed that in 2100, air temperature is expected to increase up to 4.9 °C in desert regions, this effect will produce an increase of 34.5% in cooling load, and 73% of the not comfortable rate in the buildings; while in the same year, in the coldest regions, the air temperature is expected to increase up to 5.5 °C, producing a decrease of heating load up to 15.5%, and an increase of comfort rate up to 25%. The thermal comfort temperature range was between 23.9 °C and 29.8 °C. In desert regions, the heating loads are very low, indeed, they represent only 6.5% of the total loads (loads used for cooling and heating), while in the coldest regions, the cooling loads represent only 7.3% of the total loads.

Experimental and numerical study of wind tower integrated with solar heating unit to meet thermal comfort in buildings during cold and sunny climate conditions

Natural ventilation techniques are increasingly being adopted in recent times due to the need to cut down on greenhouse gases emission and energy cost. A classic natural ventilation technique, the wind tower, may be utilised to minimize the load on typical HVAC systems. One of the major disadvantage limiting the deployment of wind tower is the additional heating load it demands on the HVAC system during the winter months. The work focusses on improving the year-round capability of a wind tower by attaching a solar heating unit (SHU) that would heat the incoming ambient air through a conjugate heat transfer system before being circulated into the space to be ventilated. For performance validation, the numerical technique was utilised initially, then an experimental setup was created based on the numerical results to validate for practical situations. Using the CFD simulation, ventilation performance of this tower system was evaluated in terms of mean age of air (MAA) and air change effectiveness (ACE). The commercial ANSYS Fluent was used to solve the three-dimensional Reynolds-Averaged Navier-Stokes (RANS) turbulence model. The results showed that SHU has been able to heat up the incoming air of 18 °C by 5 °C–23 °C which is generally considered as a comfortable temperature range. According to the analyses of airflow rate at different incident angles through the four quadrants of tower, the maximum flow rate (0.45 m3/s) of air steam was observed at 45° incident angle. The ACE values in the inhabited space were typically near to 1.0, indicating that the ventilation air mixed up well in the ventilated zone. The wind tower performance was experimentaly investigated in terms of solar radiation variations, wind velocity variations, temperature variation in SHU and inside wind tower, and air change rate (ACR) on the experimental setup. Experimental study shows a variation of 2–4 °C in the indoor temperature and thereby ensuring optimal thermal comfort. The recommended wind speed for an effective mass flow rate is in the range of 3 m/s, and an average ACR of 25 per hour indicates that the air is being ventilated properly.

Thermal bridges in buildings of consolidated contexts in high-altitude cities. Case study: Ambato, Ecuador

This research work has been centered on the study of thermal bridges in the urban area of the city of Ambato, this city is located at an altitude of 2570m with an average temperature of 15°C throughout the year, the construction systems used in the study area mostly consist of a layer of material either clay brick or concrete block and exterior and interior finishing’s. The objective is to diagnose the points where thermal leaks can be found in consolidated environments and to provide possible solutions in different construction elements. The methodology used is based on a mixed study, which analyzes the urban context, the buildings present, the construction materials used, their relationship with the current climate of the area and the quantification of latent temperatures for further simulation. The results were obtained through a calculation software where the diagnosis and the improvement plan were simulated to increase the ambient temperature of the houses from 15-17°C to the range of 20-24°C within the comfort temperature range for interior spaces. This study concluded that it is possible to significantly improve the thermal performance of buildings in consolidated contexts with specific interventions.

High-transmittance pNIPAm gel smart windows with lower response temperature and stronger solar regulation

Improving the solar regulation and reducing the response temperature of thermochromic smart windows are pivotal importance for energy-saving buildings. However, such two strategies are challenging to be integrated into one window. Herein, a solution for simultaneously regulating the surface tension of the scattering center and the capturing-releasing capacity of pNIPAm for water is implemented, successfully carrying out the enhancement of solar regulation and the reduction of response temperature. The maximum solar shielding and regulation of the modified sandwich structured pNIPAm gel device can reach up to 88.45% and 71.81%, an increase of 52.29% and 73.71% respectively, compared to a pure pNIPAm gel device with the same thickness. Besides, the response temperature is reduced to around 28 ℃, making modified devices have the ability to respond promptly at the comfortable room temperature range boundary (22–28 ℃). Different from flowing, strengthless modified doped microgels, the high-transmittance modified pNIPAm gels maintain the stable patterning performance, and have great potential for further applications. Similar conclusions are obtained using different solvents to reduce the attraction between pNIPAm-water, and the surface tension of water. Therefore, this universal modification framework deserves attention for the future design of energy-saving windows.

Comparison of Thermal Comfort Condition of Naturally Ventilated Courtyard, Semi-Outdoor and Indoor Air-Conditioned Spaces in Tropical Climate

Universiti Tun Hussein Onn Malaysia (UTHM) elibrary is in the hot and humid tropical climate of Malaysia and has a distinctive feature of a circular courtyard and semi-outdoor spaces for practical public spaces and energy saving. This study was conducted on the ground level of the library which consists of an open terrace consisting of a cafeteria, a garden in the circular courtyard, and an air-conditioned seminar room. This study aimed to compare the thermal comfort condition of these spaces through physical and subjective measurements. Physical measurement was conducted for air temperature, relative humidity, air velocity and mean radiant temperature at the two selected sampling points on each investigated area positioned at 0.6 meters from the floor. Data were collected for three days in each area during two periods of time; 9 to 11 am and 2 to 4 pm. Subjective measurements were also collected through the distributed questionnaire to 150 respondents to determine the thermal sensation votes (TSV) of each investigated area. Calculations based on physical measurement showed the thermal comfort for both the cafeteria and garden were within 90% thermal comfort acceptability limit. PMV value for the air-conditioned seminar room was -0.45 with a PPD value of 9.03%. Both results complied with the ASHRAE 55 Standards for the acceptable condition for both naturally and air-conditioned spaces. The regression analysis showed that the comfort air temperature range based on the human response method for semi-outdoor spaces and indoor spaces were 24.8 0C to 29.0 0C and 20 0C to 23.5 0C respectively. The PMV regression analysis showed that the comfort air temperature range for indoor space was 22.4 0C to 23.5 0C. Results of the study showed that respondents perceived a higher comfort temperature range in the courtyard and cafeteria compared to indoor air-conditioned spaces, but still within the recommended range of ASHRAE 55 standard. The results of the study concluded that semi-outdoor places can potentially be designed as practical public spaces for comfortable and sustainable spaces.

The thermal behavior and flame retardant performance of phase change material microcapsules with halloysite nanotube

Phase change material (PCM) has the potential to be added in coatings for energy-saving while the drawback of low thermal conductivity, poor thermal stability and flammability restrict its application. In this study, a novel halloysite nanotube (HNT) doped PCM (H-PCM) microcapsule was successfully prepared and applied in epoxy resin (EP) coatings (H-PCM-EP) to achieve temperature control. Many characteristics of the prepared PCM microcapsule were examined such as surface morphology, phase transformation performance and combustion data. The results indicated that the H-PCM microcapsule with a clear core-shell structure were successfully prepared. In comparison with the pristine PCM microcapsule, the H-PCM microcapsule had better thermostability and thermal conductivity. While the melting process of capric acid in H-PCM microcapsule advanced from 31.62 °C to 31.04 °C when compared with PCM microcapsule, which was considered as the bridge-like function of HNT. Moreover, the flammability and temperature control ability of H-PCM-EP were also investigated. The data of the peak heat release rate, total heat release, and total smoke release showed that the addition of HNT in PCM microcapsule can significantly reduce the influence of PCM in EP composites on fire hazards. Notably, the results of the small room model test and infrared thermal imager suggested that the application of H-PCM-EP can regulate inner room temperature and maintain a comfortable temperature range with less fluctuation. These properties will promote the application of the H-PCM microcapsule in temperature control coatings.

A Review of Thermal Comfort in Residential Buildings: Comfort Threads and Energy Saving Potential

Residential buildings instigate a vital role in creating a safe and comfortable indoor living environment. The phenomenon of overheating, an impact of climate change, can cause a negative effect on residents’ productiveness and heat-related illnesses and can even force high pressure on electricity generation by increasing the risk of power outages due to excessive peak cooling and heating requirements. Various issues on building thermal comfort are being evolved and discussed in review articles. However, there are few articles that review the current condition of adaptive thermal comfort studies and the potential for energy savings in residential buildings. Therefore, the aims for this paper are to: identify comfort temperature ranges in residential buildings, investigate the correlation of comfort temperature with indoor and outdoor temperatures with the aid of ‘comfort threads’, and clarify the effect of adaptive measures on residential energy saving potential. This study obtained a large variation of residential comfort temperatures, which mostly depend on the climate and operation modes of the building. ‘Comfort threads’ explains that people are adapting to a large variation of indoor and outdoor temperatures and the wide range of comfort temperature could provide significant energy savings in residential buildings. This review provides insight on and an overview of thermal comfort field studies in residential buildings.

Potential use of recycled materials on rooftops to improve thermal comfort in sustainable building construction projects

The study has two objectives. First, it experimentally measures the indoor and outdoor temperatures of a building in Peshawar and conducts validation with CFD modeling. Second, it simulates the building with the addition of locally available, natural, and recycled insulator materials on the rooftop to keep the indoor environment within a comfortable temperature range, especially in the winter and summer seasons. To achieve these objectives, experimental temperature data for January and June were recorded and validated, followed by a simulation, using ANSYS-Fluent 16 CFD, of the residential building with the application of waste thermal insulators such as straw bale, sheep wool, and recycled glass materials on the rooftop to reduce the indoor temperature. Experimental temperature measurement showed that the lowest recorded indoor temperature was 15°C on 2 January 2022 and that the highest recorded indoor temperature was 41°C on 11 June. The predicted and validated temperature results were similar, with a slight difference of less than 15%. Recycled glass positively and significantly reduced the indoor temperature in summer by 10.2% and thermal amplitude by 48.3%, with a time lag increase of 100% and an increase in the period of comfort hours of 380%. In winter, the daily average temperature increased by 7.4%, thermal amplitude was reduced by 59.3%, and the time lag increased by 100% in comparison with the baseline case results. The study concludes that recycled glass distribution gives the best improvement compared to straw bale and sheep wool.

Energy poverty, temperature and climate change

We examine the effect of temperature shocks on the proclivity to be in energy poverty and combine our estimates with simulated weather data to predict the effect of global warming on the incidence of energy poverty over the rest of the century. To do so, we match representative household panel data for Australia with weather data at a geographically localized level. We find that each additional ‘cold day’ (average temperature below 15 °C) increases the incidence of energy poverty by 0.01%–0.03%, compared to if the day had been in the comfortable temperature range (20-24 °C). We find that global warming can be expected to result in modest decreases in the extent of energy poverty in the short-medium and long-run. Most studies have emphasized the economic and social costs of climate change. Our findings are important in pointing to a specific outcome for which climate change may be beneficial for a large country with a relatively mild climate.

Experimental and Co-Simulation Performance Evaluation of an Earth-to-Air Heat Exchanger System Integrated into a Smart Building

Building models and their connected subsystems are often simulated as standalone entities. However, in order to monitor a system′s reactions to changing parameters and to assess its energy efficiency, it must be exposed to the actual dynamic context of the building under study. Hence, frameworks assessing co-operative simulation of buildings and their subsystems should be used. In this study, the Building Control Virtual Test Bed (BCVTB) framework was used for co-simulation of a small-scale building (EEBLab) connected to an Earth-to-air heat exchanger (EAHE). The EnergyPlus tool was used to simulate the indoor air temperature variations within the EEBLab, and MATLAB was used to model the EAHE system and to calculate its performance based on various parameters. The HOLSYS internet of things platform was deployed to monitor and collect the experimental data from the sensors to validate the simulations. A favorable agreement between the experimental and simulation results was obtained, showing the contribution of the small-scale EAHE system in maintaining a comfortable indoor temperature range inside EEBLab. Moreover, it demonstrated the effectiveness and accuracy of the proposed approach for integrated building co-simulation and performance evaluation.

Integrating phase change material in building envelopes combined with the earth-to-air heat exchanger for indoor thermal environment regulation

To utilize the combined effects of earth-to-air heat exchanger (EAHE) and phase change material (PCM) in indoor thermal environment regulation during summer, this study proposes a combination mode, i.e., EAHE–PCM. In this method, EAHE continuously provides cool air to indoor spaces. PCM integrated into building envelopes stores excess cold provided by EAHE at night and transfers it indoors across time. We performed two full-scale comparative experiments (EAHE–PCM combined operation mode and PCM alone operation mode) on typical summer days in hot-summer and cold-winter regions. The results showed that the maximum reduction in the EAHE outlet air temperature and moisture content reached 21.6 °C and 4.55 g/kg, respectively, inducing an average cooling capacity of approximately 1186.5 W. The use of EAHE decreased the time-averaged PCM internal temperature by 6.0 °C in 24 h compared to the PCM alone operation mode, thereby activating the phase change process of PCM between 19:54 and 9:45. Therefore, PCM can store excess cold provided by the EAHE via latent heat and transfer it to indoor air through the melting process, resulting in a 157 min lag in the PCM internal temperature rise. When the ambient air temperature varied between 26.3 and 45.2 °C, the EAHE–PCM combined operation mode decreased the time-averaged indoor air temperature by 6.6 °C compared to the PCM operation alone, which helped maintain the indoor air temperature within the comfort temperature range of 22–28 °C for 73% in 24 h, with a peak temperature of 30.6 °C.

Thermal Properties of Novel Phase-Change Materials Based on Tamanu and Coconut Oil Encapsulated in Electrospun Fiber Matrices

The accumulation of thermal energy in construction elements during daytime, and its release during a colder night period is an efficient and green way to maintain a comfortable temperature range in buildings and vehicles. One approach to achieving this goal is to store thermal energy as latent heat of the phase transition using the so-called phase-change materials (PCMs). Vegetable oils came recently into focus as cheap, widely available, and environmentally friendly PCMs. In this study, we report the thermal properties of PCMs based on tamanu and coconut oils in three configurations: pure, emulsion, and encapsulated forms. We demonstrate the encapsulation of pure coconut- and tamanu-oil emulsions, and their mixtures and mixtures with commercial PCM paraffins in fiber matrices produced by a coaxial electrospinning technique. Polycaprolactone (PCL) was used as a shell, the PCM emulsion was formed by the studied oils, and sodium dodecyl sulfate (SDS) and polyvinyl alcohol (PVA) were used as emulsifiers. The addition of commercially available paraffin RT18 into a 70/30 mixture of coconut and tamanu oil, successfully encapsulated in the core of a PCL shell, demonstrated latent heats of melting and solidification of 63.8 and 57.6 kJ/kg, respectively.

Thermal Comfort of Indoor Open Spaces at University Library in Malaysia

The issues of improving thermal comfort inside the building have become a global point of research interest attributed to the realization that people spend more than 90% of their time in the indoor environment. This study investigated the thermal comfort temperature range for indoor open spaces in second level of the Universiti Tun Hussein Onn Malaysia (UTHM) library. The study conducted through subjective measurement (thermal sensation questionnaire) and physical measurement (air temperature, relative humidity, air velocity, mean radiant temperature measurement). A total of 120 occupants completed the thermal sensation questionnaire of indoor open spaces for morning and afternoon sessions for six days. Physical measurements data were also collected at eight measurement sampling point across the indoor open space for six days. The linear regression analysis for air temperature with thermal sensation vote (TSV) and predicted mean vote (PMV) for both morning session and afternoon session shows a good fit of the regression model on the observed data. It shows 70% of the variation in the output variable of TSV and PMV can be explained by the input variables of air temperature. The thermal comfort temperature ranges for TSV of -0.5 to +0.5 were within the range of 24.17 ºC to 25.01ºC for morning session and 23.63 ºC to 24.20 ºC for the afternoon air temperature. In addition, the thermal comfort temperature ranges for PMV of -0.5 to +0.5 were 24.03 ºC to 25.15 ºC for morning session and 23.70 ºC to 24.47 ºC for the afternoon. By using linear regression equation, the relation between air temperature, PMV and TSV were obtained.

Effect of the air supply angle of swirling diffusers on the air diffusion performance index in a vehicle assembly workshop

Airflow improvement in a large industrial building is one of the most effective ways to improve the thermal comfort of workers. Air Diffusion Performance Indices (ADPI) of an industrial workshop area under different air supply angles (15°, 30°, 45°, 60°, 75° and 90° in summer and 90° in winter) of the ceiling-mounted swirling diffusers were evaluated by on-site measurements and computational fluid dynamics (CFD) modelling. The measurement data was used to verify the CFD numerical model. The temperature and velocity field of the working area were simulated and analysed under seven operating conditions of swirling diffusers. The findings showed that in summer, the increase of the swirling air supply angle would increase the air velocity. When the air supply angle was larger than 75°, a draughty wind speed (>0.3 m/s) in the local working area, was produced. When the air supply angle was 30°–75°, the indoor design comfortable temperature range (26°C–28°C) was produced. The ADPIs of the workshop were 100% with the air supply angles of 45° and 60° in summer and 90° in winter, respectively. The research findings should provide a reference for improving the airflow organization in the working area of a tall factory building.

Simulation of the Regulation Law of Buildings With Unbalanced Heating by Using the Method of Partition Intermittent Heating

Abstract Central continuous heating is widely used in China. Due to the large heating area, the indoor temperatures of the buildings with the same heat source are quite different, which affects comfort and wastes energy. This paper proposes a subsection intermittent heating method, that is, an intermittent heating method is used for overheated buildings. During the period, when the overheated buildings stop heating, the hot water originally supplied to the overheated buildings is supplied to the underheated buildings. We investigated the indoor temperatures of some actual buildings in Daqing city. Accordingly, a comfortable indoor temperature range was determined. The indoor temperature and heating energy consumption of overheated and underheated buildings with zoned intermittent heating were simulated using EnergyPlus. The results show that the interval time has important effects on the indoor temperature and energy consumption of overheated buildings. The most ideal partitioned intermittent heating regulation method is to stop heating (at 5 o’clock) for 3 h and then resume heating for 5 h. When the area ratios of overheated buildings and underheated buildings are 1:1, 2:1, and 3:1, the average indoor temperatures of underheated buildings can be increased from 16 °C to 17.65 °C, 19.05 °C, and 21.02 °C, respectively. The hot water temperature and insulation thickness have significant effects on the indoor temperature of underheated buildings.

INVESTIGATION OF THE THERMAL COMFORT AND PRODUCTIVITY IN JAPANESE MIXED-MODE OFFICE BUILDINGS

This study investigates the overall comfort and productivity of Japanese office workers in mixed-mode office buildings. The indoor thermal environment is adjusted using the air-conditioning in Japanese office buildings to maintain thermal comfort and productivity. Thus, it is necessary to research thermal comfort and productivity to understand how occupants prepare themselves to be at a comfortable temperature and perform their daily tasks under mixed-mode (MM) and free-running (FR) modes. Environmental parameters such as air temperature, relative humidity, and so on were measured in 17 Japanese office buildings with the help of digital instruments, and thermal comfort transverse surveys were conducted for two years in Tokyo, Yokohama, and Odawara of Japan. The data were collected every once a month for a day visiting each building with the measurement instruments, together with the questionnaires. Almost 3000 votes were collected. This paper evaluates the overall comfort discussions followed by how the occupant could achieve their productivity. The occupants were found to be thermally comfortable and productive in the office. The most suitable comfortable temperature range for MM mode was found to be 22–26 °C and 23–25 °C for FR mode. The workers' productivity range is defined by the globe temperature range of 21–27 °C for MM and 20–27 °C for FR mode. The findings should be useful to suggest that whenever new office buildings are designed, these factors always need to be taken into consideration.

Drivers of at-vessel mortality of the blue shark (Prionace glauca) and oceanic whitetip shark (Carcharhinus longimanus) assessed from monitored pelagic longline experiments

Elasmobranchs make up a significant part of bycatch in pelagic longline fisheries, whose induced mortality can be a major threat to endangered species. It is therefore crucial to understand the drivers of at-vessel mortality (AVM) for this fishing gear to enhance postrelease survival. To this end, we analysed scientific data collected during monitored longline fishing experiments conducted in French Polynesia to ( i) estimate AVM for each species based on bootstrapped samples and ( ii) to assess AVM drivers using multivariate logistic regression models for the blue shark ( Prionace glauca) and oceanic whitetip shark ( Carcharhinus longimanus). We found that AVM varies widely between species. Oceanic whitetip sharks are more likely to die when caught in waters outside their comfort temperature range, and their odds of survival increase with body length. For the blue shark, the only driver related to AVM is hooking duration. These results indicate that to reduce the AVM of these two species, the vertical distribution of hooks and soak duration should be considered as mitigation measures related to pelagic longlining.

MXene aerogel-based phase change film for synergistic thermal management inspired by antifreeze beetles

To survive extreme weather, antifreeze beetles have a smart thermal management system, which relies on light absorption by the black surface and energy storage by antifreeze proteins. Inspired by the energy storage behavior of antifreeze proteins, we design a composite film, which is fabricated via impregnation of organic phase change material (PCM) in a surface-modified MXene/bacterial-cellulose aerogel. The resulting composite aerogel-based PCM film shows an increased loading capacity of organic PCM, increased phase change latent heat, and enhanced mechanical properties. Combining these thermal insulation and thermal energy storage properties, a submillimeter-thick film with an aerogel layer can maintain a comfortable temperature range for more than 800 s. This is more than double compared to the system without the films, and is a proof of concept for bioinspired photothermal-conversion/thermal-storage integration. • The energy storage behavior of the antifreeze proteins is demonstrated • A MXene/bacterial cellulose aerogel-based phase change film is fabricated • The phase change film integrates photothermal conversion and energy storage/release • Bioinspired synergetic thermal management maintains comfortable temperature for ∼800 s The thermal regulation of antifreeze beetles relies on light absorption by black surfaces and energy storage by antifreeze proteins (AFPs), allowing them to survive extreme weather. Ji et al. demonstrate the energy storage behavior of AFPs and fabricate a surface-modified aerogel-based phase change film, achieving bioinspired thermal management behavior through the integration of photothermal-conversion and thermal storage.