Performance testing and modeling of a transpired ventilation preheat solar wall : performance evaluation of facilities at Fort Drum, NY, and Kansas Air National Guard, Topeka, KS

This work performed measurement and verification of installed, operational solar wall systems at Fort Drum, NY, and Forbes Field, Air National Guard, Topeka, KS. Actual annual savings were compared estimated savings generated by a solar wall modeling tool (RETScreen). A comparison with the RETScreen modeling tool shows that the measured actively heated air provided by the solar wall provides 57% more heat than the RETScreen tool predicted, after accounting for boiler efficiency. The solar wall at Fort Drum yields a net savings of $851/yr, for a simple payback of 146 years and a SIR of 0.16. RETScreen models indicate that the solar wall system at Forbes Field, Kansas Air National Guard, Topeka, KS saves $9,350/yr, for a simple payback of 58.8 years and a SIR of 0.34. Although results showed that, due to low natural gas prices, the Fort Drum system was not economically viable, it was recommended that the system still be used to meet renewable energy and fossil fuel reduction goals. The current system becomes economical (SIR 1.00) at a natural gas rate of $16.00/MMBTU or $1.60 /therm.

ENHANCING THERMAL COMFORT OF RESIDENTIAL BUILDINGS THROUGH A DUAL FUNCTIONAL PASSIVE SYSTEM (SOLAR-WALL)

ABSTRACT Thermal comfort has a great impact on occupants’ productivity and general well-being. Since people spend 80–90% of their time indoors, developing the tools and methods that enhance the thermal comfort for building are worth investigating. Previous studies have proved that using passive systems like Trombe walls and solar chimneys significantly enhanced thermal comfort in inside spaces despite that each system has a specific purpose within a specific climate condition. Hence, the main purpose of this study is to design and configure a new, dual functional passive system, called a solar wall. The new system combines the Trombe wall and solar chimney, and it can cool or heat based on building needs. Simulation software, DesignBuilder, has been used to configure the Solar Wall, and study its impact on indoor operative temperature for the base case. Using the new system, the simulation results were compared with those obtained in the base case and analyzed to determine the most efficient system design parameters and implementation method. The case that gave the best results for solar wall configuration was triple glazed glass and 0.1 cm copper as an absorber (case 11). The results show that using four units (case D) achieves longer thermal comfort levels: 15 to 24 thermal hours during winter (compared to five hours maximum) and 10 to 19 comfort hours in summer (compared to zero).

Thermal Characteristics and Parametric Analysis of an Improved Solar Wall

Solar air collectors installed on buildings can significantly reduce conventional energy consumption in winter and summer. However, some problems arise in the utilization process, such as overheating, inconvenient operation control and low energy efficiency, etc. This work is a parametric analysis focusing on the automatic control and thermal efficiency improvement of the solar wall. An improved color-changing solar wall integrated with automatic control components, such as a photoelectric fan and temperature-controlled damper, was proposed in this paper. Based on the experimental data, the average daily heat output of the color-changing solar wall is 1.08 MJ per unit floor area on clear days in winter and the average thermal efficiency is 56.8%. Meanwhile, a quantitative analysis was carried out based on monitoring experiments for evaluating the thermal characteristic of automatic control components. Furthermore, in order to improve the thermal performance of the solar wall, parametric analysis was performed by numerical simulation. Results from this paper can provide a theoretical basis for the application of solar air collectors in modern buildings.

Selection of Parameters for Accumulating Layer of Solar Walls with Transparent Insulation

One of the strategies to improve the energy performance of buildings may be the use of passive solar systems with transparent insulation. In the article, a numerical model of solar wall (SW) with transparent insulation (TI) obtained using the method of elementary balances is presented. On this basis, numerical simulations of the behavior of SW with a transparent honeycomb insulation made of modified cellulose acetate were performed for 4 different climatic conditions in Europe (Stockholm, Warsaw, Paris, and Rome). For each location, the calculations were carried out for three different TI thickness values (48, 88, and 128 mm), for thermal diffusivity of the accumulating layer (AL) ranging from 4.32 × 10−7 to 8.43 × 10−7 m2/s, and for its thickness ranging from 0.1 to 0.5 m. The purpose of simulations was to select the appropriate material and thickness of AL and TI for the climatic conditions. The following solutions proved to be the most favorable: Stockholm: TI—thk. 128 mm, AL—sand-lime blocks, thk. 25 cm; Warsaw: TI—thk. 128 mm, AL—sand-lime blocks, thk. 27 cm; Paris: TI—thk. 88 mm, AL—solid ceramic brick, thk. 27 cm; Rome: TI—thk. 48 mm, AL—solid ceramic brick, thk. 29 cm.

ENHANCING THERMAL COMFORT OF RESIDENTIAL BUILDINGS THROUGH DUAL FUNCTIONAL PASSIVE SYSTEM (SOLAR-WALL)

ABSTRACT Thermal comfort has a great effect on occupants’ productivity and general well-being. Since people spend 80–90% of their time indoors, developing the tools and methods that help in enhancing the thermal comfort for buildings are worth investigating. Previous studies have proved that using passive systems like Trombe walls and solar chimneys significantly enhanced thermal comfort in inside spaces despite that each system has a specific purpose within a specific climate condition. Hence, the main purpose of this study is to design and configure a new dual functional passive system, called a solar wall. The new system combines the Trombe wall and solar chimney, and it can cool or heat based on building needs. Simulation software, DesignBuilder, has been used to configure the Solar Wall and study its impact on indoor operative temperature for the base case. Using the new system, the simulation results were compared with those obtained in the base case and analyzed to determine the most efficient system design parameters and implementation method. The case that gave the best results for solar wall configuration was triple glazed glass and 0.1 cm copper as an absorber (case 11). The results show that using four units (case D) achieves longer thermal comfort levels: 15 to 24 thermal hours during winter (compared to five hours maximum) and 10 to 19 comfort hours in summer (compared to zero).