Heat Loss Coefficient Research Articles

Dynamic testing of a new integrated collector storage solar water heater (ICSSWH) according to standard ISO 9459‐5: Use of a numerical approach for long‐term prediction in different climatic conditions

AbstractThis work analyzes the performance of a new Integrated Collector Storage Solar Water Heater (ICSSWH) by using Dynamic System Testing (DST) method according to Standard ISO 9459‐5. The long‐term performance study of the system in different climatic conditions has been achieved by a coupling model between DST results and a numerical approach based on the system transient behavior. Results of the experimental dynamic system evaluation showed that the total store heat capacity Cs, the useful collector surface Ac* and the storage tank heat losses coefficient Us are, respectively, 0.87 MJ/K, 1.21 m2 and 10 W/K. In Tunisian climatic conditions, the ICSSWH system allows covering until 79.3% from a typical family need for a daily consumption of 170 L. The results found allow optimizing the energy gain of the ICSSWH as well as selecting a specific load volume according to the location. Especially, investigations showed that in Stockholm and Riadh climatic conditions, the ICSSWH's solar fraction reached 27% and 83%, respectively, for a daily load volume of 250 L. More importantly, the experimental effort of DST identification can be minimized by coupling DST data with a robust numerical approach.

A Mechanistic Model Based on Statistics for the Prediction of a Converter’s End-Point Molten Steel Temperature

With the high efficiency and automation of converter smelting, it is becoming increasingly important to predict and control the endpoint temperature of the converter. Based on the heat balance, a model for predicting the molten pool temperature in a converter was established. Moreover, the statistical method of multiple linear regression was used to calculate the converter heat loss coefficient, greatly improving the prediction accuracy of the mechanistic model. Using the model, the oxidation process for each element in the molten pool, the melting processes of scrap, and the flux were also calculated. The model could better approximate the actual smelting process. Data from a 130 t converter were collected to validate the model. When the error ranges were limited to ±20 and ±15 °C, the model hit rates were 96 and 86.7%, respectively.

Energy and Exergy Analysis of a Rectangular-Shaped Mini-Channel Flat-Plate Solar Collector Using Tio2-Water and Cu-Water Nanofluids

Flat plate solar collectors (FPSC) are commonly used for a variety of applications and have a very simple design. However, the main drawbacks of the collector are its low outlet temperature and poor thermal performance. In present study, the fluid outlet temperature, heat removal factor, energy efficiency, exergy efficiency, and pressure drop have been evaluated for a rectangular-shaped minichannel FPSC operating with two different nanofluids (Cu-water and TiO2-water). The ranges of volumetric concentration ratio and mass flow rate are 1-5% and 0.01-0.07kg/s, respectively. A mathematical model based on the energy balance has been solved using energy equation solver software. The result revealed that fluid outlet temperature, mean plate temperature, and overall heat loss coefficient (HLC) increase with increasing concentration ratios for both nanofluids. But at the same concentration ratio and MFR, the fluid outlet temperature, mean plate temperature, and overall HLC for Cu-water nanofluid are greater than those of TiO2-water. The outlet temperature and mean plate temperature for the nanofluid TiO2-water of volumetric ratio 1% are 369.4K and 347.9 K, respectively, and these values increase to 395.9K and 351.1K at volumetric ratio 5% for the same MFR of 0.01 kg/s. Efficiency and heat removal factor for the TiO2-water nanofluid are greater than those for the Cu-water nanofluid for the same MFR and concentration ratio. Pressure drop increases with increasing concentration ratios for both fluids, but it is greater for Cu-water as compared to TiO2-water.

Experiment and model of a photovoltaic module with evaporative cooling

Most studies on evaporative cooling of photovoltaic modules have primarily relied on experimental investigations without any general model to investigate the module performance. In this paper, an experimental model similar to that of solar collector performance was developed in terms of total efficiency and ratio of temperature difference between cooling fluid and ambient temperatures with solar radiation for finding the module thermal characteristics which were optical efficiency and module overall heat loss coefficient, the module temperature, and then the generated electrical power. To validate the model, experimental tests were conducted on a 320 Wp monocrystalline photovoltaic module of 1.956 m × 0.992 m area equipped with an evaporating surface at the module rear surface on some clear sky and cloudy days in Chiang Mai, Thailand. The evaporating pad was made of cellulose and polypropylene with 5 mm thickness. A controlled flow rate of water at 0.3 L/min was maintained with inlet temperatures ranging between 25 and 35 °C, ensuring a non-dripping condition. The results from the new simplified model demonstrated good agreement with the experimental data. In addition, the developed model was also used to predict the yearly performance of the photovoltaic module with evaporative cooling under tropical climate of Chiang Mai. The average total and net monthly electrical output were increased 7.04 and 4.47%, respectively compared to that of the normal unit. In case of hot and arid area such as Ouargla, Algeria, better improvement of PV module performance could be attained, and the average total and net monthly power generation could be enhanced 8.62 and 6.48%, respectively.

Impermeable Graphene Skin Increases the Heating Efficiency and Stability of an MXene Heating Element.

A Joule heater made of emerging 2D nanosheets, i.e., MXene, has the advantage of low-voltage operation with stable heat generation owing to its highly conductive and uniformly layered structure. However, the self-heated MXene sheets easily get oxidized in warm and moist environments, which limits their intrinsic heating efficiencies. Herein, an ultrathin graphene skin is introduced as a surface-regulative coating on MXene to enhance its oxidative stability and Joule heating efficiency. The skin layer is deposited on MXene using a scalable solution-phased layer-by-layer assembly process without deteriorating the excellent electrical conductivity of the MXene. The graphene skin comprises narrow and hydrophobic channels, which results in ≈70 times higher water impermeability of the hybrid film of graphene and MXene (GMX) than that of the pristine MXene. A complementary electrochemical analysis confirms that the graphene skin facilitates longer-lasting protection than conventional polymer coatings owing to its tortuous pathways. In addition, the sp2 planar carbon surface with a low heat loss coefficient improves the heating efficiency of the GMX, indicating that this strategy is promising for developing adaptive heating materials with a tractable voltage range and high Joule heating efficiency.

Experimental study of phase change material performance as thermal insulation of a double-walled spherical tank under partial vacuum for storing solar energy

In solar systems, conservation of stored energy is even more important than energy storage. In this study, as an innovative idea, the thermal behavior of a phase change material (PCM) is investigated as thermal insulation of an energy storage tank based on the unique feature of phase change at a constant temperature. Condition for creating an ideal insulation is the existence of a heat source at the border. The PCM surrounding the tank stores the solar energy latently in the process of thermal charging, and as a heat source in the process of thermal discharge. By releasing energy at a constant temperature through the PCM, the heat loss factor that is the temperature difference between the hot water and the surface of the tank is controlled. The PCM shows three different behaviors as the thermal insulation. One, as long as the energy stored in the PCM is sensibly released, the heat loss coefficient is almost constant, in which the PCM acts as a super insulator. Two, by releasing the latent energy, the heat loss coefficient tends to zero, and the PCM acts as an ideal insulator. Three, by releasing all the stored energy, the PCM acts as a normal insulator. Creating the relative vacuum between the tank and the glass cover improves the thermal performance, thereby the hot water temperature decreases by 7.4 °C in the best case, and the thermal efficiency reaches 85%.

In-situ assessment of the thermal performance of earth masonry construction

The interest in traditional earth constructions has grown in Europe since a few years. This growing interest can be attributed to the fact that earth has among other qualities a good capacity for the hygrothermal regulation inside a building. This well-established ability of earth to store and manage heat and moisture has been extensively studied in the past at the material scale. However, the evaluation of the building envelop performance is rarely achieved in practice. This study presents an evaluation of the thermal performance of earth masonry construction based on in-situ measurements under real conditions of exposure. The construction consists of a single unoccupied room with habitable surface area of 12.9 m2 located in Canohès in the Southern France. Firstly, the airtightness of the envelop was quantified with the blower door test. The air permeability results indicated a very good level of airtightness. Then the thermal insulation of the envelop was measured according to the ISABELE method (In Situ Assessment of the Building EnveLope pErformances). The latter is a method developed by the CSTB to deduce the transmission heat transfer coefficient of the building with its uncertainty within short unoccupied period (few days). The results of the different ISABELE tests demonstrated that the total thermal insulation level of the tested envelop could be classified as good to average according to the scale of the building heat loss coefficient (Ubat) of the French Energy Performance Diagnosis. The results of the ISABELE tests were confirmed by the outcomes of a Coheating test conducted during a long period of 3 months. This study gives encouraging results on the application of the ISABELE method on earth masonry buildings to deduce the thermal performance of their envelope quickly, instead of a complete Coheating test which can be too long to apply in practice.

Thermal Performance Characterization of Evacuated Tube Collector Solar Water Heater with Constant Inlet Water Temperature

Abstract: With large evolution in the solar technology, research is turned out to be more sophisticated. Evacuated tube collectors (ET Collectors) are the most eco-friendly and efficient solar water heaters used worldwide. A series of experiments have been performed on ETC Characterization System. The research presents the evaluation of the performance of an ET Collector and characterize the solar water heater at different wind velocity of (2, 3, 4 m/s) and solar radiation between 250 to 750 W/m2 by keeping temperature of inlet water as constant. Examining the system performance at different temperature of inlet water of (29 °C, 40 °C, 50 °C). Net heat loss through evacuated tubes (ETs), heat loss coefficient through ETs, & the efficiency of an ET Collector has been recorded.

Study on collection and retention efficiencies of a new integrated collector storage solar water heating system using a planar thermal diode: an experimental study.

Thermal diodes are a novel method to rectify the heat transfer mechanism and help reduce heat losses in solar thermal collectors during non-collection periods. The current study introduces and analyzes a new planar thermal diode integrated collector storage (ICS) solar water heating system using an experimental approach. This thermal diode ICS system has a simple, affordable structure composed of two parallel plates. Water serves as a phase change material to transfer heat through evaporation and condensation inside the diode. Three scenarios were considered to assess the dynamics of the thermal diode ICS: atmospheric pressure, depressurized thermal diodes, and Ppartial = 0, - 0.2, and - 0.4bar. The water temperature reached 40°C, 46°C, and 42°C in Ppartial = 0, - 0.2, and - 0.4bar, respectively. The heat gain coefficients are 38.61, 40.65, and 39.26 W/K, while the heat loss coefficients are 9.56, 5.16, and 7.03 W/K in Ppartial = 0, - 0.2, and - 0.4bar, respectively. The optimum heat collection and retention efficiencies are 45.3% and 33.5% in Ppartial = - 0.2bar. Hence, there is an optimum partial pressure to achieve the best performance, equal to - 0.2bar. The acquired results illustrate the robustness of the planar thermal diode in reducing heat losses and rectifying the heat transfer mechanism. Furthermore, despite the simple structure of the planar thermal diode, its efficiency is as high as that of other types of thermal diodes analyzed in recent studies.

Evaluation of Convective Heat Transfer and Natural Circulation in an Evacuated Tube Solar Collector

The evacuated tube solar collector ETC is studied intensively and extensively by experimental andtheoretical works, in order to investigate its performance and enhancement of heat transfer, for Baghdad climatefrom April 2011 till the end of March 2012. Experimental work is carried out on a well instrumented collectorconsists of 16 evacuated tubes of aspect ratio 38.6 and thermally insulated tank of volume 112L. The relationbetween convective heat transfer and natural circulation inside the tube is estimated, collector efficiency, effect oftube tilt angles, incidence angle modifier, The solar heating system is investigated under different loads pattern (i.eclosed and open flow) to evaluate the heat loss coefficient from tank and tubes, test the collector with variousaspect ratios (32.9 and 27.2). The enhancement in collector performance is studied by using two reflectors (FlatPlate and Curved Plate) and nanofluid (Water-AL2O3).Theoretical work is run by software (Fluent 6.3), to computethe velocity and temperature profiles within the tube, for different tube diameters, effect of tube junction angle andstagnant region in the bottom of the evacuated tube. The experimental results shows that the heat loss coefficientfor tube is W/m2.K and for tank is W/m2.K, the maximum collector temperature is 79°C in winter and99°C in summer, while that belong to nanofluid collector is 99°C in winter. The best tilted angle (optimum) ofevacuated tube is 41° annually. The collector efficiency increased when using nanofluid of (1, 0.6, 0.3)% volumefraction as(28.4, 6.8, 0.6)% respectively. The efficiency decreases as (33, 62)% when decreasing tube aspect ratiofrom 38.6% to 32.9% and 27.2% respectively. An increase of (16.9 and 7.08)% in collector efficiency is obtainedwhen using curved and flat plate reflectors respectively. From simulation the best junction angle of the tank is22.5°. The stagnant region is influenced with changing heat flux, tilted angle and aspect ratio.

Impact of solar gain estimation on heat loss coefficient determination using in-situ data: Comparing co-heating test with B-splines integrated grey-box modelling

This study investigates the estimation uncertainties of grey-box models, with increased complexities of quantifying solar gain dynamics, in building energy performance assessment. The precision of solar gain estimation has been proven to be crucial for delivering a qualified grey-box model and achieving a better performance in predictive applications, e.g., model predictive control (MPC). Therefore, grey-box models that characterize solar gain dynamics more precisely are generally preferred. However, characterizing solar gain dynamics with more elaborated details might estimate solar gain dynamics more precisely but enlarge the uncertainties in accessing the buildings' overall energy performance, e.g., determining the buildings’ overall heat loss coefficient (HLC). Hence, this study aims to understand this potential risk. At first, four types of solar gain estimation approaches available for grey-box models are systematically summarized. The four grey-box models are applied to two datasets monitored on a full-scale lightweight building, under two scenarios of effective window distribution. The study reveals that enhancing the solar gain modelling in grey box models does not hamper a reliable HLC-determination in this case. Moreover, it was found that under certain conditions a more precise estimation of the solar gain can even reduce the uncertainty of the HLC-estimate via narrowing 95% confidence interval.

A data-driven method for heat loss estimation from district heating service pipes using heat meter- and GIS data

District heating (DH) pipes are often older than 20 years and of unknown condition, imposing a strong demand for detailed knowledge about their current state to help cost-effective ongoing renovation and reduce water and energy losses. Here, we develop a scalable method that exploits hourly resolved remotely read heat meter data, pipe coordinates, and soil temperature measurements to continuously estimate the heat loss of service pipes. The method does not require the measured or simulated flows in the full system, making it possible to omit the usual step of establishing a complete thermohydraulic network model which is currently hindering implementation on larger scale. By exploiting open-source soil temperature data, the estimated heat loss is normalized to output the transmission coefficient, U, in W/(m∙K), allowing for direct intercomparison between pipes of different length and assessment of timely evolution across seasons. Estimated heat losses are validated by complementary techniques, using simulation of data sets and highly time-resolved data from a test area with additional measurement equipment installed. Finally, a full-scale application is demonstrated over a year on 1089 service pipes, including detection of a spontaneously emerged leakage, revealed through the model sensitivity towards the consequential changes in heat loss coefficient, U.

Effects of Stack Structure and Heat Loss on the Stability and Efficiency of Steam-Methanol Reforming Microreactors for Hydrogen Production

The linear scale-out approximation ignores the influence of exterior heat loss and thus cannot address extinction issues. The present study is focused primarily upon the roles of stack structure and heat loss in the stability and efficiency of microreactors for hydrogen production by steam-methanol reforming. Computer simulations are performed to model the complex physicochemical processes in a variety of different heat loss situations. The effects of channel number, wall thermal conductivity, and surface-area-to-volume ratio are investigated to assess the importance of stack structure and heat loss in microreactor design. The results indicate that the total heat loss becomes increasingly significant for designing reactors with small stacks of channels. About half of heat released is lost if a global-type extinction occurs. The critical heat loss coefficient depends heavily upon the number of channels. The design with a large stack of channels more closely beneficially improves heat utilization and reduces heat loss. There is a significant linear relationship between energy efficiency and heat loss coefficient. Significant heat loss may cause extinction in edge channels while still permitting very high conversion in center channels. The wall thermal conductivity is of vital importance to ensure stability operation. Higher wall thermal conductivity provides stability benefits, but walls with very low thermal conductivity can be employed to reduce heat loss by sacrificing the thermal coupling capability.

Evaluation of Energy Production using Parabolic-Dish Solar Collector: A Case Study of Iraq

The parabolic dish reflector solar collector is one of the significant and most efficient steam-producing solar concentrating systems in thermoelectric power plants and, furthermore, it's considered to be environmentally friendly (renewable energy). Iraq has vast land for installing solar collectors to generate steam and use for thermal power plants. However, no such application/power plant has yet been built. Therefore, the proposed study investigates opportunities for using PDR solar collectors, including all advantages and challenges. To implement and estimate the productivity and efficiency of the PDR in (Diyala City / Iraq), a PDR solar collector with a total area of 0.708 m2 (including the glass pieces used as a reflective surface) was designed and fabricated. These glass pieces have been utilized to increase the reflection of solar rays by 80% when compared to a traditional case/setup. Two different systems (open and closed) were considered to investigate the performance of thermal power . The results show that the absorption temperature was increased from 34.6 to 95 °C. On the other hand, the coefficient of heat loss by convection increases by about (795.5 W). In addition, it was pointed out that the coefficient of total heat loss over time was increased by about 25 to 41% (closed and open systems). Furthermore, the experimental findings clearly demonstrate the usefulness of PDR solar heaters in Iraq. Hence, its confidently believed that this research will be useful in the future for this type of thermal power plant.

Experimental investigation on the impact of fin structure factors on the finned-Trombe wall thermal performance

By increasing surface area, fins can enhance the heat transfer and improve the Trombe wall thermal performance. However, there is still a lack of detailed experimental research on the impact of fin structure factors on the thermal performance of finned-Trombe wall (F-TW). This experiment establishes a platform under laboratory conditions to investigate the impact of fin height and spacing on the F-TW thermal performance. Electric heating is used to simulate the solar radiation. The results indicate that in areas with relatively low solar radiation intensity, the F-TW is more cost-effective for improving F-TW thermal performance. The F-TW thermal parameters including air temperature rise, mass flow rate, thermal efficiency and overall natural convective heat transfer coefficient are enlarged as the fin height increases and fin spacing decreases, while the heat loss coefficient of glass cover is opposite. The fin spacing has a more significant influence on the F-TW thermal performance and natural convective heat transfer in the channel than the fin height does. The maximum thermal efficiency of 63.75% is obtained at heat flux of 860W/m2, relative fin height of 0.75 and relative fin spacing of 0.06. Finally, for the engineering design and performance assessment of F-TW, the experimental correlation is provided to calculate the average natural convective heat transfer Nusselt number in the channel.

Quantitative thermal-wave depth profiles of solids with spatially variant cooling coefficients imaged using lock-in thermography

A generalized treatment of the thermal-wave boundary-value problem in a solid slab strip with large sidewalls exposed to the ambient and third-kind boundary conditions over the extended sidewall surfaces was presented. Unlike conventional heat conduction theoretical practice, it was found that the cooling coefficient h is not constant and depends on the thermal gradient variation with depth/length. The exponential damping of the TW amplitude with depth presented an ideal condition to reveal the depth dependence of h which under normal steady heat transfer conditions might appear approximately constant in a non-steeply changing thermal field. The observed depth dependence of the heat loss coefficient can be used to establish the physically expected constancy of thermal diffusivity at different modulation frequencies in juxtaposition to some published reports. It is expected that this work can be used to optimize other thermophysical parameters for materials subject to periodic heating.

Thermal assessment of a new planar thermal diode integrated collector storage solar water heater in different partial vacuums: An experimental study

Thermal diodes are novel mechanisms with high thermal resistance in one direction and low thermal resistance in the other. The current study introduces a new planar thermal diode integrated collector storage (ICSs) system and analyzes its transient dynamics and performance under field conditions in several scenarios, including operating at atmospheric pressure and partial vacuums: Ptotal = 0.7 atm and 0.5 atm. The acquired data illustrate that the collector has approximately the same transient dynamics during the collection period, while differences pronounce during the retention period. Utilizing partial vacuums is tricky and may cause to decrease in performance; however, the best retention and collection efficiencies were obtained at 16.97% and 29.33% when Ptotal = 0.7 atm was utilized. Increasing the partial vacuums to Ptotal = 0.5 atm decreases the retention efficiency significantly to nearly 3.26%. The heat gain (forward mode) coefficient was not affected significantly by partial vacuums. However, the heat loss (reverse mode) coefficient was reduced by nearly 17.63% at Ptotal = 0.7 atm compared to atmospheric pressure. The calculated heat gain and heat loss coefficients are 9.28 W/k and 19.65 W/k at Ptotal = 0.7 atm; hence, the constructed thermal diode successfully serves as a unidirectional heat transfer mechanism.

Experimental studies of latent heat storage based solar air heater for space heating: A comparative analysis

There are numerous applications of solar energy technology, among which an air heating system is commonly used for space heating, wood seasoning, industrial drying, etc. Previous research focuses on the bulk usage of different latent heat storages, which is a costly method for performance improvement, especially for solar heating systems. Another major problem with bulk energy storage is that it takes a long time to be charged completely, which results in low-rate air heating at the start. The present research focuses on an economical solution for solar air heating, especially under India's mild cold climatic conditions. About 36 tiny cylindrical containers have been used to carry the two low-cost phase change materials (PCMs), i.e., coconut oil and paraffin wax. These materials have been filled inside the small containers and placed over the solar absorbers of modified models of air heaters, namely, SAHS-2 (with coconut oil) and SAHS-3 (with paraffin). A total of 02 configurations have been developed to conduct the air heating trials on natural and forced convection. To the best of the author's knowledge, likely methodology has not been applied to any air heating system to improve performance for extended hours, especially in a cold climate. Results have been compared with the same size conventional solar heater (SAHS-1) and some other relevant designs of SAHS to observe the significance of PCMs and their appropriateness for air heating. Finally, the model SAHS-3 is found to be the best-configured air heater, capable of performing efficiently under mild cold climates. Experimental studies showed that the best model provides enhanced heat transfer of about 372.81 W/m2 K, thermal efficiency of about 75.9%, a heat loss coefficient of about 4.93 W/m2 K, and outlet air temperature of about 44.07 °C under forced convective operations. The estimated cost of the modified heater is approximately $61, while its payback period is about 4.38 years.

Experimental and Numerical Simulations of a Solar Air Heater for Maximal Value Addition to Agricultural Products

Agriculture is the backbone of Pakistan’s economy. Currently, the agricultural sector is facing many challenges, especially post-harvest losses, which result in lower yield and profitability. These losses may be reduced by developing indigenous post-harvest processing technologies, such as drying out of agricultural products to enhancement of their sustainability and reduce transportation costs. The country has the advantage of an abundant amount of solar insulation, which can be effectively utilized to operate post-harvest machinery, particularly solar heaters and dryers. Currently, conventional solar heaters face challenges due to lower efficiencies. Therefore, in this study, a solar air heater (SAH), having a size 1220 × 610 × 65 mm, was designed and developed to be connected to a milk powder spray drying system for converting raw milk to powder. Computational fluid dynamics (CFD) were used to anticipate air flow and temperature distribution across the SAH to evaluate optimal performance parameters. An air mass flow rate of 0.01 kgs−1 was required, with the CFD predicting an outlet temperature of 82 °C compared with the experimental observation of 73 °C. The pressure drop across the SAH was recorded to be 0.0000434 bar at this flow rate, which is negligible, with the SAH operating near ambient pressure. The overall heat loss coefficient for convection was 2.27 W. m −2·K−1. The energy losses from the SAH were 37% and the useful energy was 63% of the total energy provided to the SAH. The breakeven point of SAH at a minimum of 4 h of daily usage was 3700 h or 2.5 years. The solar air heater used as a preheater for a spray dryer can save 30 PKR·kWh−1 of energy.

Cooking performance assessment of a phase change material integrated hot box cooker.

Previous research on solar box cookers focusing on the bulk usage of energy storage materials is a costly technique for performance enhancement. Bulk energy storage materials take much time to charge and, thus, result in a low rate of cooking at the start. Therefore, a hot box solar cooker has been developed and experimentally studied for thermal performance enhancement in a hilly region of Uttarakhand, India. A bed of phase change material (paraffin wax) filled with small capsule-shaped containers was prepared (detachable) and placed over the cooking tray of the tested cooker. These containers were vertically positioned over the bed to enhance the heat transfer rate inside the cooker to attain a fast-cooking response. Notably, the combined effect of extended geometry with PCM is an excellent method to increase the efficiency of a solar cooker. As per the author's knowledge, likely techniques have not been studied for a box cooker to achieve a fast-cooking rate in any hilly region up to date. The results of cooking tests show that the cooking plate attained a maximum temperature of about 150°C. It is because of the combined effect of extended fins (vertical capsules) and PCM filled inside them. The results of the experimental study show that the thermal efficiency of the cooker was found to be about 45.7%, the cooking power was calculated about 54.71W, the heat transfer coefficient was estimated about 311W/m2 °C, and the overall heat loss coefficient was computed about 5.71W/m2 °C. This modified cooker costs about $48.19, and the payback period is about 03years and 11months. Cooking trials also showed that the present SBC could cook almost all the dishes commonly cooked in Uttarakhand.