Conventional Heating Systems Research Articles

Synergy of ball milling, microwave irradiation, and deep eutectic solvents for a rapid and selective delignification: walnut shells as model for lignin-enriched recalcitrant biomass

The combination of ball milling (BM), microwave irradiation (MI), and deep eutectic solvents (DES) results synergistic for an efficient, selective, and very rapid (10 min) delignification of materials with high lignin content (ca. 50 wt%) such as walnut shells (WS). Lignin is dissolved in the DES, whereas the polysaccharide fractions remain suspended with limited degradation, due to the rapid pretreatment. After ball milling procedure (3 h), biomass loadings in the range of 100–200 g L−1 are selectively delignified in 10 min at 150 °C by using choline chloride:formic acid DES (1:2 molar ratio), rendering lignin yields of 60–80% (ca. ~ 40–60 g lignin L−1). Ball milling, microwave irradiation, and DES systems are much more efficient than ball milling, conventional heating, and DES system. The obtained lignins exhibited similar Fourier-transform infrared spectroscopy (FTIR) profile to that of milled wood lignin (MWL), indicating minimal functional group changes.Graphical abstract

Preliminary Study on Optimization of a Geothermal Heating System Coupled with Energy Storage for Office Building Heating in North China

Geothermal heating is considered to be one of the low-carbon-energy technologies for building heating. Aiming at the problem that the operating cost and investment cost of geothermal heating systems are still high, the conventional geothermal heating system coupled with energy storage for office building heating is studied in this paper. Four operational strategy models of the coupled system are established based on time-of-use electricity prices. A genetic algorithm is used to find the optimal value of each decision variable using minimization of levelized cost of heat (LCOH) as the objective function. The influences of electricity and equipment prices on the optimal values of the decision variables are discussed. Four operation strategies are investigated. If only operating cost is considered in the optimization, comparison shows that the best operation strategy is the one giving high priority to use the energy storage tank for heating during the peak electricity period. However, if the investment cost is further considered in the optimization, the best operation strategy is the one using the energy storage tank for heat load peak-regulating. In addition, based on the minimization of LCOH, an optimal energy storage ratio is found for each scenario, and suitable conditions of using energy storage tank are discussed. The geothermal heating system coupled with energy storage can have a good performance when the peak-valley electricity price difference is higher than CNY 0.566/kW·h (USD 0.0847/kW·h)+ or the energy storage tank price is lower than CNY 900/m3 (USD 134.64/m3). The results obtained from this study prove that the cost of geothermal heating systems can be effectively reduced by choosing an optimal operation strategy and using an energy storage device with an optimal energy storage ratio.

The experimental study of energy features for solar air heaters with different turbulator configurations

AbstractTo assess the thermal performance in the climate conditions of western and central Iraq, the advantages of using a solar air collector with various turbulator absorber plates are experimentally explored. Four distinct kinds of absorber plates are provided flat plate (F), triangular (T), rectangular (R), and circular (C) turbulators at different air mass flow rates. The collector's economic properties and overall thermal performance are compared to the conventional flat plate turbulator heating systems. The main findings suggest that delta turbulators improve collector economics and overall thermal performance by generating vortex and dampening the formation of the thermal boundary layer in the direction of airflow. Furthermore, when the mass flow rate increases, the thermal performance improves, and the efficiency increases for all mass flow rates, resulting in good thermal performance for the rectangular plate collector when compared to other collectors. When compared to other types of configurations, the daily average efficiency of solar air collectors for flat plate (F), triangular (T), rectangular (R), and circular (C) turbulators are 28%, 67%, 39%, and 48%, respectively, at 50° tilt angle while at 90° tilt angle they are 44%, 76%, 54%, and 63%, respectively, as ṁ = 0.0377 kg/s. The maximum daily average efficiency fitted with rectangular turbulators have about 86% at the largest ṁ = 0.1 kg/s. This study will also give a unique direction to the work trend in the western and central parts of Iraq throughout the winter months.

Analysis of the Air Quality of a District Heating System with a Biomass Plant

Heating is one of the major causes of pollution in urban areas, producing high concentrations of aero-dispersed particulate matter (PM) that can cause serious damage to the respiratory system. A possible solution is the implementation of a district heating system, which would decrease the presence of conventional heating systems, reducing PM emissions. The case study considered involves the municipality of Serra San Bruno (Italy), located near a biomass plant, which could play the role of a thermal conversion plant for a possible district heating network. To determine the heating incidence on pollution, the large users in the area were identified. The large users’ consumption estimation was carried out, obtaining the thermal energy requirement linked to the residential, which is about 3.5 times that of all the large users. Through air quality measuring devices, PM concentrations were measured for the winter and the summer period. PM emissions were then estimated using emission factors and the decreases in PM concentrations were calculated if part of the domestic users were converted to district heating, compatibly with the possibility of supplying energy to the biomass power plant. The replacement of conventional plants in favor of a district heating network has a positive impact on PM pollution.

Thermal storage integrated into air-source heat pumps to leverage building electrification: A systematic literature review

Air-source heat pumps (ASHPs) can support a decarbonized economy by replacing combustion appliances in homes and electrifying heating systems in buildings. However, ASHPs have not seen significant adoption primarily due to deteriorated performance under cold conditions—at very low temperatures they require auxiliary resistance heating to meet the heating demand and defrost the evaporator. The additional heat lowers the system efficiency. Thermal energy storage (TES) is a candidate technology to help overcome some of these issues. This paper presents a systematic literature review to map the existing research on the integration of TES into ASHPs. Our review of 59 publications indicates that thermal storage increases the ASHP coefficient of performance by 27% on average, albeit with higher initial cost compared to conventional fossil-fueled heating systems. Phase change materials may be ideal to be integrated with ASHPs due to their high energy density and compact design, but only a few publications address TES sizing and design. First and Second Laws of Thermodynamics are widely used to create metrics to assess ASHP-TES integration, and only recently have cost and environmental impact been explored. This literature review suggests that more comprehensive metrics are needed to evaluate the potential benefits of ASHP-TES systems. • In ASHP-TES systems the most common configuration is TES operating as a buffer • TES was also applied in heat exchangers, waste heat, and hybrid solar systems • Defrosting was addressed in 37% of the papers included in the SLR • Latent materials appeared in 63% of the reviewed works • Only recently metrics like C O 2 emission and costs have been employed in ASHP-TES

Performance evaluation and multi-criteria decision analysis of thermal energy storage integrated geothermal district heating system

Geothermal energy use in district heating systems has been prevalent and familiar in areas with rich sources for many years. In conventional geothermal district heating systems (GDHS), the geothermal fluid is transported to a heat center to give its heat energy to the secondary fluid. Then, this secondary fluid is circulated in the city network to give its heat energy to the heating circuit by the heat exchangers in the substations. Finally, the geothermal fluid is re-injected to handle the continuity of the resources. This current system works under the designed conditions of a heating system with significant electricity consumption and enormous heat waste. In this study, a thermal energy storage (TES) system was integrated into substations instead of heat exchangers to prevent the waste of heat and overconsumption of electricity by obtaining just-in-time working conditions. In this regard, a shell and tube latent heat TES system was designed for residential use for peak loads and integrated into the heating circuit of GDHS, preserving the current main structure. A number of 37 available cases were formed parametrically to evaluate the system's performance. These cases were analyzed thermodynamically by energy and exergy methods. The net present value (NPV) method was used to evaluate the cases' economics. Finally, an efficiency analysis technique with output satisficing (EATWOS) was conducted to determine the most efficient design from the viewpoints of exergy efficiency, NPV, and CO2 emissions.

Heat distribution concepts for small solar district heating systems – Techno-economic study for low line heat densities

• Two novel distribution concepts are compared to conventional district heating. • A novel distribution system with central domestic hot-water heating is presented. • Hybrid distribution outperforms a conventional steel pipe system. • A complete low-temperature system outperforms hybrid distribution. • Reduction in line heat density favours a low-temperature GRUDIS system. The high operating temperatures in today’s district heating networks combined with the low energy demand of new buildings lead to high relative network heat losses. New networks featuring lower operating temperatures have reduced relative heat losses while enabling an increase in the use of solar heat. The primary aim of this study was to determine if a particular district heating system can be made more effective with respect to heat losses and useful solar energy, by considering different distribution concepts and load densities. A small solar assisted district heating system with a novel hybrid distribution system has been modelled based on a real case study. This model serves as a basis for two other models where the distribution system and heating network operating temperature is changed. A secondary aim of the study was to determine the economic implications of making these changes, by using costs estimates to calculate the contribution of essential system components to total system cost. Results indicate that a novel distribution concept with lower network temperatures and central domestic hot water preparation is most energy efficient in a sparse network with a heat density of 0.2 MWh/m∙a and a performance ratio of 66%, while a conventional district heating system performs worst and has a performance ratio of less than 58% at the same heat density. In an extremely sparse network with heat density of 0.05 MWh/m∙a, the performance ratio is 41% and 30% for these systems, respectively. A simple economic analysis indicates that the novel distribution concept is also best from an economic point of view, reducing the initial investment cost by 1/3 compared to the conventional concept, which is the most costly. However, more detailed calculations are needed to conclude on this.

Energy Assessment and Economic Study of Solar Floor Heating System in Different Climates in Morocco

Abstract Currently, the development of energy production projects in the building sector using alternative energy sources such as solar energy is growing rapidly. This increasing technological progress to achieve the needs of comfort and safety can be considered a major priority, particularly with concerns about energy shortages and current environmental issues threatening not only human well-being but ecosystems as well. The present research aims to provide a comprehensive model for enhancing the energetic performance of rural Moroccan houses, by exploring solar radiant heating systems. The evaluation of the solar floor heating system is carried out by trnsys to evidence the effect of various design parameters on performance indexes of the system concerning six Moroccan cities, which representatively correspond to the Moroccan climatic zoning. The examined analyses cover the effect of the collector area, storage tank volume, and mass flowrate in the solar loop and the building heating loop. Moreover, how the variation of thickness and piping material affect the performances was discussed as well. The major finding of this work is optimizing the system performance gives the possibility to meet adequately the heating load. The energetic analysis shows the system's adaptability to the Moroccan climate, whose solar fraction is around 65% and 87%. For most of the examined sites, it was observed that the demand for auxiliary energy is limited from October to May. The economic investigations revealed that payback periods of the examined system ranged between 7 and 13 years. Besides, the energy and economic outcomes of such systems in Morocco, they are capable to mitigate the huge amount of CO2 emissions as compared to conventional heating systems.

Fast, High Quality and Low-Cost Biodiesel Production using Dolomite Catalyst in an Enhanced Microwave System with Simultaneous Cooling

In this study, biodiesel production with canola oil and methanol in the presence of dolomite catalyst was examined in a multimode Enhanced Microwave System (EMS) with simultaneous cooling worked under constant, continuous microwave (MW) power and isothermal conditions. The experiments were carried out in the EMS utilizing the "one variable at a time" method to estimate optimum values of five experiment parameters named methanol-to-oil molar ratio (nm/no), amount of catalyst (% wt of oil), temperature (T,°C), reaction time (t, min) and absorbed MW power (Pa,W). The optimum values of these parameters were obtained as 9, 5%, 65°C, 120 min., 48 W, respectively. At the end of the study in EMS, an experiment was repeated in the Conventional Heating System (CHS) at the optimum conditions. Accordingly, it was found that the yield of biodiesel in EMS (99.1%) during the same period was 30.2% higher than in CHS (76%). Faster, higher-quality, and lower-cost biodiesel production was accomplished when compared to the CHS. Energy and production cost saving were accomplished by 58.2 % and production rate was increased by 30.4% in EMS. Furthermore, selective and homogenous heating effect on catalyst's local surface temperature and strong vibrational effect of MW on dipoles provided advantages in terms of catalyst activity and different methyl ester content. This showed that biodiesel with different properties can be produced using same oil in the EMS.

Greening of the District Heating Systems—Case Study of Local Systems

The integration of renewable energy resources into district heating systems is gaining momentum across Europe, as heat producers are expected to work towards the EU Directive of Efficient District Heating and Cooling to achieve carbon neutrality by 2050. This paper studies the techno-economic implications of transforming conventional district heating systems of six locations in Poland, generating 8.5 PJ of heat annually, into sustainable and efficient district heating systems. These new systems consist of flat solar collectors integrated with seasonal pit thermal energy storages and gas heating plants, acting as flexible heat sources, covering residual heat demand and/or increasing the parameters of the working medium in the network. Using the IEA-TIMES software, two scenarios were considered, namely STAT and DYN. The results show that reaching a 20% share of heat production by solar thermal would demand extra construction of seasonal heat storage facilities with a total capacity of 197 TJ, which is approximately 4.5 times bigger than the largest seasonal heat storage located in Vojens, Denmark. The projected increase in the prices of natural gas and CO2 emission allowances accelerates the transformation of systems towards greater use of solar heating plants. In the period 2025–2050 the heat generation costs increase by ca. 65%. The contribution of the CAPEX and OPEX costs components are presented.

Energy analysis of a wood or pellet stove in a single-family house equipped with gas boiler and radiators

In the residential sector, biomass appliances are widely used for space heating and often combined with other systems. This work aims at comparing the final and primary energy consumption of different configurations, including a conventional and a ducted pellet stove and a wood log stove using air as heat transfer fluid. A dynamic analysis of the interaction between biomass stoves and conventional heating systems, such as gas boilers and radiators, is carried out within a typical single-family house in a mild climate, using TRNSYS software. In addition, natural ventilation of the building is considered using CONTAM, with a focus on external infiltrations and internal air circulation due to the buoyancy effect. Results show that the biomass device in one room promotes the airflows between adjacent thermal zones, enhancing the heat distribution through door openings, in particular when an air ducted stove is present. The final energy consumption resulting from simulations with wood-burning stoves is 21% higher than pellet stoves. The pellet stove results in similar final energy and a 30% increase in overall primary energy, while the wood stove increases the final energy by 22% and approximately 40% of overall primary energy compared to the case of a traditional gas system coupled to radiators which is considered as reference. Nevertheless, non-renewable primary energy savings are higher than 50% with pellet stoves and 60% with wood-log stoves.

Occupants’ on-demand control of individual heating devices in rural residential buildings: An experimental scheme and on-site study

A better understanding of actual heating demands is crucial for optimizing operational heating systems, because disparities between expected load and actual demand are key factors in inefficient heating system design, implementation, and corresponding energy loss. Additionally, the discrete, energy consumption-based billing systems applied to freestanding rural residential buildings encourages reductions in energy waste but produces spatially and temporally distinct heating patterns. Conventional heating systems have only basic controls and slow response times that cannot reflect actual user demand. Hence, this paper presents an experimental scheme for measuring room-wise heating demands, and thus, the actual heating demand patterns of rural residential buildings. A case study was conducted on a typical rural residential building in Beijing to validate the method’s feasibility. Real-world usage patterns were obtained using indoor environment sensors and independently-controlled heating devices that collected the operational parameters of each room over three years, in a long-term non-intervention study design. Clustering analysis and various indicators were used to characterize heating demand for each room: heating patterns, usage intensity, and temporal variation. In most case, the occupants heated only a few rooms, rather than the whole building. These results have potential real-word implications for predicting occupant heating behavior and energy conservation.

Modelling of cooling radiant cubicle for an office room to test cooling performance, thermal comfort and energy savings in hot climates

The building industry challenges have led researchers to develop a personalized conditioning system aiming to create a microclimate comfort zone around the occupant. Radiant cooling become prevalent due to their potential in affording both comfort and energy saving. Consequently, this study investigates the performance of a personalized cooling radiant cubicle (PCRC) combined with a conventional heating, ventilation, and air-conditioning (HVAC) system in an office room in hot climates. PCRC performance is assessed by introducing a novel model that combines computational fluid dynamics (CFD) and mathematical simulation based on two criteria: the ability in creating a thermal comfort zone near the occupant at high set-point temperatures and the economic feasibility in terms of energy savings and pay-back period. The results demonstrate that PCRC (i) maintains a comfortable personal thermal environment in the desired zone (ii) reduces the thermal asymmetry (iii) improves the corresponding predicted percentage of dissatisfied (PPD) index. When compared to published experiment, it is shown that the developed model is valid with a maximum relative error of 5% underlining its accuracy and eliminating the need of a full-physics based model. Moreover, implementing PCRC reduces cooling energy by 18% compared to conventional system with a payback period between 6 and 7 years.

Economic feasibility of heating source conversion of the swimming pools

Conversion from conventional heating systems is developed to address the emission of CO2 in the environment, global warming, rising costs, potential shortages of fossil fuels, for all energy source alternatives available. This study reviewed the economic feasibility associated with converting the current heat source to a renewable energy source of heating swimming pools located in Jordan. Many modern heating systems techniques are proposed in this study such as solar heat collectors, heat pump and photovoltaic assisted heat pump. Solar heat collectors are a device that collects and/or concentrate solar radiation from the sun and allow for heating the water. In addition, a growing interest in photovoltaic/heat pump systems is considered, which combines photovoltaic cells and heat pump systems. Hence converting solar energy into electricity and then heat through the heat pump. The Initial and operation cost for all proposed techniques is evaluated. As a result, it is found that the best economical alternative option that can be installed on the available area of the building is photovoltaic with a heat pump system during the heating season. The operation cost of the current source (diesel boiler) is about 179,974 US$ and the total cost of heat solar thermal collector is about 936,540 US$ but the total cost of the proposed photovoltaic/heat pump system is nearly 251,060 US$, which save about 45,134 US$ yearly of the total commercial building electricity bill that is selected with a payback period of fewer than two years. In addition, available space on the rooftop of the selected building is well fitted with photovoltaic panels which are around 2000 m2. This result suggests that utilizing a PV/HP system for hotel pools is advantageous both financially and environmentally.

Microwave-based extractive metallurgy to obtain pure metals: A review

Although metals are fundamental to the economy and human well-being, natural ore depletion is inevitable with the continuation of mining. Awareness of the importance of new developments in technologies to process natural ores and to recycle waste materials to obtain pure metals with high efficiency has been growing over time. The microwave-based furnace, which heats samples rapidly, uniformly and selectively, has recently been given more attention as an alternative to the conventional heating systems. However, the current progress of microwave technology for obtaining pure metals has not been fully monitored. This study reviews the extractive metallurgical approaches for obtaining pure metals by subjecting virgin materials and waste materials to the microwave heating method. In this paper, the principles of the microwave-based furnace to heat the samples are first summarized. Then, the studies of microwave-based pyrometallurgical and hydrometallurgical approaches to produce the virgin metals and to recycle metals are abridged. Finally, the limitations of current progress and the future prospects of microwave-based metallurgical technology are identified. A number of clear advantages of microwave irradiation emerged through the review process. The two most noteworthy advantages are that some materials difficult to reduce using conventional technology can be treated effectively using microwave irradiation, and microwave technology has the potential for a number of materials to facilitate a more rapid chemical reaction with fewer impurities considering the more than 50% of reduction in the apparent activation energy under microwave irradiation.

Analysis of Energy and Exergy of a Two-Circuit Solar Installation with Thermosiphon Circulation

In this paper, a new system is proposed to improve the thermodynamic and economic indicators of solar room heating. The heat pump is integrated with a conventional solar heating system, in which the temperature of the collected heat is reduced by 20 °C to 30 °C to increase the efficiency of solar energy collection. The low-temperature heat collected by the solar collector is increased using a heat pump to generate high-temperature heat for indoor heating in winter and low-pressure process steam for industrial use in other seasons. The results show that the efficiency of the solar collector has increased by 30.50%, its annual effective operating time has reached 2000 hours, which is about four times more than that of a conventional solar heating system. In addition, the parameters of the solar collector area, the volume of the storage tank and the power of the heat pump have been optimized. This work provides a new way to use solar energy more efficiently and economically. Energy analysis shows that with the new flat solar collectors, the average annual values were 2.5 kW, and also high, the COP system in November was 4%.

Optimization of a Radiant System for Hydrothermal Performance Using Taguchi and Utility Concept

Abstract Radiant floor panel technology is gaining popularity as an alternative system over the conventional heating, ventilation, and air conditioning system to maintain the room temperature for the desired comfort. This research paper aims to optimize the hydrothermal performance of a radiant system by implementing the Taguchi technique and utility concept for cooling and heating mode of operation. Five geometrical and thermal parameters such as pipe diameter, pipe spacing, concrete layer thickness, wall temperature, and inlet and outlet water temperature difference with three levels are chosen as controlling factors to perform optimization. Considering five parameters and three levels, a total of 27 trial runs (L27) are constructed and computed by mathematical calculation. Two different sets of optimum parameters are obtained for maximizing heat flux and minimizing pressure drop. Furthermore, the utility concept is employed to get a single set of parameters to achieve maximum utilization of the radiant system. Taguchi analysis revealed that thermal parameters like temperature difference and wall temperature are the most influential parameters to reach maximum heat transfer and minimum pressure drop followed by geometrical parameters like pipe spacing and diameter for heat flux and pressure drop, respectively. Providing more weightage to heat flux than pressure drop, utility analysis showed 32% and 42% augmentation in heat flux for cooling and heating mode, respectively, at the cost of an increase in pressure drop.

Performance evaluation of a hybrid heating system combined a groundwater source heat pump with an existing fuel oil heater for a horticultural greenhouse

ABSTRACT This paper reports a new hybrid heating system (HHS) installed in a horticultural greenhouse to lower the impact of high and unstable fuel prices on the greenhouse operation cost, to save the energy necessary to heat the greenhouse, and to reduce CO2 emissions. The HHS consisted of a groundwater source heat pump system for basic heating and an existing fuel oil heater for peak heating. The performance of the HHS, including the fuel oil and energy savings, and CO2 emissions reduction, was evaluated based on measurements during a heating period from November 2014 through May 2015. The results show that, comparing with only using the existing fuel oil heater to heat the greenhouse, the HHS can save 74.4% fuel oil and 22.8% energy, and reduce 35.5% CO2 emissions. In order to further increase the performance of the HHS, the operating control of the HHS, indoor hot air delivery system, and local thermal insulation of the greenhouse were improved. Performance evaluation based on measurements from November 2015 through May 2016 shows that the improved HHS can save 88.0% fuel oil and 35.9% energy, and reduce 48.7% CO2 emissions, which are significantly higher than those of the HHS before improved. Moreover, the comparison indicates that the performance of HHS was almost not changed with three different groundwater pumping rates tested herein. The proposed HHS is particularly suitable for transforming conventional fossil heating systems of horticultural greenhouses into a more energy-saving and thus sustainable heating system with a comparatively low initial cost.

Appraising the life cycle costs of heating alternatives for an affordable low carbon retirement development

This paper assesses the low carbon design of housing developments for retired people who are willing to downsize. There is a need for a strategic approach to provide energy-efficient housing in general, but specifically for a growing aged population. This approach should be inclusive and affordable. Therefore, this study assessed the capital and operational costs of space and water heating of typical UK retirement dwellings by considering over a 30-year life cycle, the use, maintainability, replacement frequency, and sustainability of applying different low carbon energy technologies and renewables to various primary heating plants. Conventional heating systems (e.g. gas, electricity) and low carbon green technologies, such as photovoltaics (PV), solar hot water systems (SHW), combined heat and power (CHP) and air source heat pumps (ASHP), were studied and compared. A combination of ASHP and a SHW system reduced the energy costs by 57% maintenance costs by 14% and produced 46% lower carbon emissions than the gas boiler option. However, the ASHP option generated 75% more capital costs than the gas boiler scenarios as well as high replacement costs due to the short life expectancy of the system. The gas boiler and PV combination had the lowest capital, energy, and life cycle costs but also hadhigh carbon emissions. The results suggest that UK government incentives, such asapplying a carbon tax would significantly reduce the payback time of green technologies and could, therefore, be the key drivers of low carbon adoption.

Effect of integrating high flow naturally driven dual solar air heaters with Trombe wall

Trombe wall is one of the sustainable architectural designs in the building that offers significant opportunities for energy saving and contribute to the low green-house emissions. Naturally or buoyancy driven dual solar air heaters (SAH) are barely used in building sector with Trombe wall due to its low mass flow rates and low efficiency. In this paper, a new concept of integrating high flow naturally driven dual heating system of Trombe wall integrated with SAH has been numerically investigated, optimized and an efficient design configuration is proposed. Total seven independent configurations namely type-1 to 7 have been investigated wherein type-1 and 2 is SAH coupled with a vertical chimney, type-3 has SAH coupled with Trombe wall, and type-4 to 7 are SAH coupled with Trombe wall having bell-mouth inlet opening for improved hydraulic performance for rapid space heating. It is observed that if Trombe wall is integrated suitably with bell-mouth inlet, SAH along with chimney, it can significantly increase the mass flow rates of heated air by about 2.5 times the convectional design. It is also observed that with increase in mass flow rates, system shows significant exergy gain of 142% when compared to conventional design. Time needed to heat a given space from a specific initial temperature are also calculated using first law of thermodynamics with mass flow values taken from the model and compared with conventional design. It was noted that to heat a given space to a desired temperature, new system of dual SAH takes about 70% less time. The proposed coupled Trombe wall-SAH device has shorter payback period and could save tons of greenhouse gas emissions annually compared to the conventional fossil fuel-based heating systems. Thermal comfort of the occupant can be enhanced with dual SAH-Trombe wall system resulting in significant energy saving.