Performance of a combined passive/active solar house

The paper describes a residence designed and built to demonstrate that active and passive solar homes could be economically by conventional home builders. The systems were designed for simplicity and cost effectiveness. The home was built in 56 days with conventional building materials and built by labourers with no particular training in energy efficient building techniques. After one season of operation the energy use data shows impressive performance. The auxiliary fuel requirement for the heating season was only 0.035 MJ/m²°C-day (1.72 Btu/ft²°F-day).

Economically the home is equally impressive. An independent appraiser of the home valued the construction at US $67 500. In reality the home cost US $59 000 including contractor's overhead and profit. Subtracting from this the amount US $4000 for the Federal Solar Tax Credit results in an owner cost of US $55 000.

The project demonstrated that given proper consideration for design, construction techniques, and solar systems integration, a solar structure need not cost more than conventional construction.     

Energy cost of building construction

The energy cost for the construction of new buildings is about 1.3 MBtu/ft² so the total U.S. annual energy cost of constructing new buildings is 5.1 quads, or one fifth the annual energy required to operate the existing stock of buildings, including residences. This analysis is based on broad SIC category analysis, and gaps exist in the knowledge. On an annual basis, steel in building construction represents 0.85 quad (16%), concrete only 0.05 quad (1%), and aluminum only 0.01 quad (0.25%).     

Seismic isolation design of the San Bernardino County Medical Center replacement project

The San Bernardino County Medical Center Replacement Project, located in Colton, California, consists of six separate building structures containing a total of approximately 920 000 ft² of floor space for hospital and support services. Five of the six buildings will be base isolated. Each of the five base isolated buildings is of different size and configuration, ranging from a six story, 360 000 ft² curved front Nursing Tower to a two story, 24 000 ft² rectangular shaped Central Plant building. The building structures will be framed with structural steel, utilizing concentric braced frames as the lateral force resisting system. The design ground motion for the site, which is located 3 km and 15 km from the San Jacinto and San Andreas faults respectively, is very severe. A base isolation system has been designed for this facility which will provide an essentially elastic building response to the design strong ground motion. The base isolation system is a hybrid passive energy dissipation system consisting of both linear and nonlinear and high damping rubber bearings along with viscous damping devices located at the base of the structure. The high damping rubber bearings provide both lateral stiffness which governs the fundamental period of vibration of the system, and hysteretic damping, while the viscous damping devices provide velocity dependent damping which serves to control overall building displacements. This will maximize the probability that this essential facility will remain fully operational after a major earthquake. Design criteria, structural analysis and design methodologies, and construction details are presented and discussed. The response of one of the base isolated structures is calculated utilizing actual recorded ground motions from the 1994 Northridge earthquake.     

Measurements of the transmission of radiation through water sprays

The effectiveness of water spray curtains in preventing fire spread depends on the amount of thermal radiation transmitted through the spray. The authors have measured the transmission of radiation through spray curtains from a sprinkler and a nozzle producing a flat spray at both high and low water pressures. They conclude that with proper nozzles, a water curtain of low transmission could be produced from water flows comparable with those of sprinkler installations. Note: The following equivalents may be helpful in perusing this paper: 1 cm=.394 in.; 1 m=3.28 ft; 1 atmosphere=14.7 psi; temperature (°C)+17.78×1.8=temperature (°F); 1 milliliter per second=.0159 gpm; 1 cal/sec/cm²=13,272 Btu/hr/ft².     

Thermal performance evaluation of a prefabricated fiber-reinforced plastic building envelope system

Fiber-reinforced plastic (FRP) materials are extensively used in building construction, primarily due to their superior structural performance characteristics. Recently, a newly-developed concept consisting of a prefabricated, interlocking fiberglass composite panel system has been adopted for use in the construction of building envelope systems. The structural characteristics of these panels allow, among other things, expeditious construction. Other performance advantages include corrosion resistance, reduced maintenance, electric insulation characteristics, and electromagnetic transparency. Since little information is available on the thermal performance characteristics of such a panel system, a testing program was developed to investigate the thermal insulation characteristics of FRP panels that are commercially available at the present. Two full-scale 1.2 m by 1.2 m (4 ft by 4 ft) FRP panels were tested. Two panel thicknesses were considered: 25 mm (1 in.) and 75 mm (3 in.). The thermal characteristics of the panels were measured including the effects of the presence of the joints between the panels. A temperature-controlled test plate, calibrated with fibrous glass board material of known thermal conductivity, was used with heat flow sensors to determine the thermal resistance of the FRP panels at the mid-sections of panels and at the interfaces (i.e. joints) between two adjoining panels. Two conditions were simulated; ‘dry joint’ which includes only mechanical interlocking at the joints, and ‘sealed joint’ in which the joints were sealed with a commercially available sealant. The R values of the tested panels were approximately 5% to 46% higher in the sealed-joint condition. Sealed joints decrease heat exchange across the envelope system, thereby increasing the thermal resistance values of the panel system. The relatively high R value of the 75 mm panel system (2.0 (m² K)/W (11.36 (h ft² °F)/Btu)) is encouraging, and makes this envelope system a potential candidate for wider use in energy-conscious commercial buildings.     

Membrane regeneration for wastewater reclamation using reverse osmosis

One of the major problems in applying reverse osmosis to wastewater reclamation is the potential plugging and simultaneous product flux-decline of the membranes. At present two techniques are prevalently used to minimize these deleterious effects. These are periodic clearing and extensive pretreatment. A third, and as yet untried, technique is presented here. It involves the in situ replacement of degraded membranes at projected replacement costs far below those for spirally wound units.Results presented here demonstrate that in situ replacement of cellulose acetate reverse osmosis membranes is technically sound. The membrane replacement cycle was repeated six times with average water fluxes of about 13 gal ft⁻² day⁻¹ and salt rejections of between 78 and 85 per cent. The regenerable unit was also tested on primary and secondary sewage effluent. Average water fluxes were between 3 and 10 gal ft⁻² day⁻¹, respectively, while salt rejections were between 66 and 73 per cent. Projected membrane costs are reduced from $4.06 ft⁻² for a 6-in. dia. module to $0.08 ft⁻² for a 72-in. dia. module. Thus, large diameter units become economically very attractive. Design and cost computer parametrization is also presented.     

A survey of municipal anaerobic sludge digesters and diagnostic activity assays

A plant site survey was made of 30 municipal wastewater treatment plants concerning the operational characteristics of their anaerobic sludge digesters. Design information, operating data and analytical data were tabulated. Samples of each sludge were then assayed to determine the residual gas production rate, the maximum potential acetate and propionate utilization rates, the 5 and 30 day biochemical methane potential (BMP₅) (BMP₃₀) and the possible limitation in bioavailability of iron, cobalt or nickel.The average solids content of the raw sludge fed to the digesters was 4. 7%. Eight of the 30 sludges showed stimulation in the gas production rate when iron, cobalt or nickel was supplemented and acetate was unlimiting. Nine of the 30 sludges showed stimulation in the gas production rate when iron, cobalt or nickel was supplemented and propionate was unlimiting.The average BMP₅ was 0. 7 volumes of methane per volume of sludge. The average BMP₃₀ was 1.9 vol CH₄/vol sludge. On average 87% of the biodegradable fraction of the sludge was converted to methane during digestion. The average maximum potential acetate utilization rate (MPAUR) was 0.93 vol CH₄/vol sludge-day. The average maximum potential propionate utilization rate (MPPUR) was 0.18 vol CH₄ /vol sludge-day. The average H₂S in the digester gas was 2200 ppm. The average digester capacity was 0.14 million gallons/million gallons per day (MG/MGD) of raw wastewater. On average the raw sludge pumping rate was 4300 gal per MG of raw wastewater. The average digester gas production was 0.066 vol gas/vol of raw wastewater (8800 ft³ per MG). The average unit gas production rate was 0. 64 volumes of digester gas per volume of digester per day. The average volume of digester gas produced per volume of raw sludge feed was 15. 8 v/v. The average gas production per pound of volatile solids added was 0. 46 m³ kg⁻¹ VS (7. 4 ft³ lb⁻¹ VS). The average gas production per pound of volatile solids destroyed was 0. 94 m³ kg⁻¹ VS (15. 0 ft³ lb⁻¹ VS).     

Hyperfiltration of laundry wastes

Hyperfiltration (reverse osmosis) with dynamically formed hydrous Zr(IV) oxide-polyacrylate membranes removed 98 per cent of the organic carbon from effluents from two commercial laundries. The filtrate was clear and essentially colorless to over 85 per cent water recovery. Fluxes were mostly between 50 and 100 (U.S.) gal day ⁻¹ ft⁻² at temperatures typical of the laundry operations and at 950 psig pressure.     

Lighting energy consumption in ultra-low energy buildings: Using a simulation and measurement methodology to model occupant behavior and lighting controls

As building owners, designers, and operators aim to achieve significant reductions in overall energy consumption, understanding and evaluating the probable impacts of occupant behavior becomes a critical component of a holistic energy conservation strategy. This becomes significantly more pronounced in ultra-efficient buildings, where system loads such as heating, cooling, lighting, and ventilation are reduced or eliminated through high-performance building design and where occupant behavior-driven impacts reflect a large portion of end-use energy. Further, variation in behavior patterns can substantially impact the persistence of any performance gains. This paper describes a methodology of building occupant behavior modeling using simulation methods developed by the Building Energy Research Center (BERC) at Tsinghua University using measured energy consumption data collected by the University of Washington Integrated Design Lab (UW IDL). The Bullitt Center, a six-story 4831 m² (52,000 ft²) net-positive-energy urban office building in Seattle, WA, USA, is one of the most energy-efficient buildings in the world (2013 WAN Sustainable Building of the Year Winner). Its measured energy consumption in 2015 was approximately 34.8 kWh/(m²?yr) (11 kBtu/(ft²?yr)). Occupant behavior exerts an out-sized influence on the energy performance of the building. Nearly 33% of the end-use energy consumption at the Bullitt Center consists of unregulated miscellaneous electrical loads (plug-loads), which are directly attributable to occupant behavior and equipment procurement choices. Approximately 16% of end-use energy is attributable to electric lighting which is also largely determined by occupant behavior. Key to the building’s energy efficiency is employment of lighting controls and daylighting strategies to minimize the lighting load. This paper uses measured energy use in a 330 m² (3550 ft²) open office space in this building to inform occupant profiles that are then modified to create four scenarios to model the impact of behavior on lighting use. By using measured energy consumption and an energy model to simulate the energy performance of this space, this paper evaluates the potential energy savings based on different occupant behavior. This paper describes occupant behavior simulation methods and evaluates them using a robust dataset of 15 minute interval sub-metered energy consumption data. Lighting control strategies are compared via simulation results, in order to achieve the best match between occupant schedules, controls, and energy savings. Using these findings, we propose a simulation methodology that incorporates measured energy use data to generate occupant schedules and control schemes with the ultimate aim of using simulation results to evaluate energy saving measures that target occupant behavior.     

The Saskatchewan conservation house: Some preliminary performance results

The Saskatchewan Conservation House, a low-energy-consumption solar-heated residential structure, began operation in December 1977. Monitoring of the house began in January 1978. The house has been operated as a demonstration dwelling seven days a week, and consequently monitoring conditions have been less than ideal, with approximately 1,000 visitors per week passing through the house. Monitoring of the energy consumption of the dwelling indicates that the design objective — a heat loss rate of 81 Watts per degree Celsius temperature difference between outside and inside — has been met and improved upon. An average Regina house has a heat loss rate of approximately 250 Watts/°C. The system uses 17.8 m² of vacuum tube collectors. As the system was not started until mid-December, 1977, it was not possible to provide 100% solar heating during this winter period. Approximately three Gigajoules of thermal energy can be stored in the 12,700-litre storage tank. Based on the measured performance of the house, a ‘space-heating requirement of 5.1 Gigajoules per year (4.8 million Btu) would be needed to heat the house under normal occupancy conditions. The system is designed to provide 100% of this space-heating requirement.     

Energy use in Minnesota State-owned facilities

This paper describes and analyzes the contents of a large data base containing information on monthly energy use at state-owned facilities in Minnesota. The data base, managed by the State Department of Administration, includes information on 42 community colleges, state universities, hospitals, prisons, and the St. Paul Capitol Complex. The data span a seven year period (1972 – 1978) and include about 3,500 observations.Several data base management issues are discussed. These include errors and their correction, development of simple and consistent definitions for key terms, and collection of information on key determinants of energy use at these facilities.Total annual energy use at these 42 institutions averaged 245 kBtu/ft² (2.78 GJ/m²) for 1978. Fossil fuels accounted for 56% of this total; electricity accounted for the remainder. Energy use at the Capitol Complex, hospitals and prisons was higher than average.Regression equations were developed to predict monthly heating fuel use and total energy use. These equations show that more than 60% of the variation in energy use per unit floorspace can be explained by a few variables: heating degree days; electricity and fossil fuel prices; number of buildings; number of boilers; facility age; and whether or not the facility is all electric.     

Sealing ducts in large commercial buildings with aerosolized sealant particles

Electricity energy savings potential by eliminating air leakage from ducts in large commercial buildings is on the order of 10 kWh/m² per year (1 kWh/ft²). We have tested, in two large commercial buildings, a new technology that simultaneously seals duct leaks and measures effective leakage area of ducts. The technology is based upon injecting a fog of aerosolized sealant particles into a pressurized duct system. In brief, this process involves blocking all of the intentional openings in a duct system (e.g. diffusers). Therefore, when the system is pressurized, the only place for the air carrying the aerosol particles to exit the system is through the leaks. The key to the technology is to keep the particles suspended within the airstream until they reach the leaks, and then to have them leave the airstream and deposit on the leak sites. The principal finding from this field study was that the aerosol technology is capable of sealing the leaks in a large commercial building duct system within a reasonable time frame. In the first building, 66% of the leakage area was sealed within 2.5 h of injection, and in the second building 86% of the leakage area was sealed within 5 h. We also found that the aerosol could be blown through the VAV boxes in the second building without impacting their calibrations or performance. Some remaining questions are: (1) how to achieve sealing rates comparable to those experienced in smaller residential systems; and (2) what tightness level these ducts systems can be brought to by means of aerosol sealing.     

Evaluation of ventilation code requirements for building crawl spaces

Building ventilation code requirements for crawl spaces were reviewed from 1937 to today and though remain largely unchanged, provide designers and builders flexibility in moisture control methods. This study evaluates the current building ventilation code requirements for at-grade and below grade crawl space using computational fluid dynamic (CFD) software with experiment inputs. The research first tested the soil moisture evaporation rate from two monitored crawl spaces in Colorado, US, which produces an average moisture load of 13.75 grains/(ft²·h) (9.6g/(m²·h)) and a maximum load of 42.7 grains/(ft²·h) (29.8g/(m²·h)). The soil moisture evaporation rates identified align well in magnitude with those recorded in the literature, supporting the estimation method used. The experiment reveals that plastic ground cover can effectively reduce the moisture load from the soil by an average of 93%. The study then developed a CFD model of the monitored crawl space to assess the necessity and effectiveness of various ventilation code requirements. The space effective leakage area to the exterior was determined through field pressurization testing and CFD analysis to be approximately 0.26in.²/ft² of floor area. The CFD predictions, validated with the measured data, verify that the building code requirements for at-grade crawl spaces appear sufficient, but have limitations for below grade crawl spaces. Sealed crawl spaces perform better in humid climates, supporting previous research, and mechanical ventilation is justified for below grade crawl spaces only. The paper provides suggestions for the revisions to the current building code to recognize below grade underfloor spaces.     

Treatment of low strength domestic wastewater using the anaerobic filter

A laboratory scale anaerobic filter packed with synthetic high surface area trickling filter media was used to treat a low strength domestic wastewater averaging 288 mg 1⁻¹ COD. The filter was operated for 60 days after reaching steady-state at 20, 25, 35°C at a loading rate of 0.02 lb COD ft⁻³ day⁻¹ and 24 h hydraulic retention time. Filter effluent BOD₅ averaged 38 mg 1⁻¹ providing an average removal rate of 79%, and effluent COD averaged 78 mg 1⁻¹, corresponding to a 73% removal rate. Removal efficiencies showed very little sensitivity to daily fluctuations in influent wastewater quality. The filter performance at 25 and 35°C was not significantly different, but BOD and TSS removal efficiency declined a: 20°C. Gas production averaged 0.027 ft⁻³ of gas per ft³ of influent wastewater, or 1.875 ft³ of gas per pound of influent COD. Gas composition averaged 30% nitrogen, 65% methane, and 5% carbon dioxide. Ammonia nitrogen and sulfides both increased during treatment. It is concluded that the anaerobic filter is a promising candidate for treatment of low strength wastewaters and that post treatment for sulfides and ammonia may be necessary.     

Experimental study of using PCM in brick constructive solutions for passive cooling

This work presents the results of an experimental set-up to test phase change materials with two typical construction materials (conventional and alveolar brick) for Mediterranean construction in real conditions. Several cubicles were constructed and their thermal performance throughout the time was measured. For each construction material, macroencapsulated PCM is added in one cubicle (RT-27 and SP-25 A8). The cubicles have a domestic heat pump as a cooling system and the energy consumption is registered to determine the energy savings achieved. The free-floating experiments show that the PCM can reduce the peak temperatures up to 1 °C and smooth out the daily fluctuations. Moreover, in summer 2008 the electrical energy consumption was reduced in the PCM cubicles about 15%. These energy savings resulted in a reduction of the CO₂ emissions about 1-1.5 kg/year/m².     

Design & practice on engineering projects of specially deep & big excavation in Shanghai

This paper briefly describes two engineering projects of specially deep and big excavation,Jin Mao Mansion and Heng Long Square with depth of 19.65m and 18.20m, and area of about 20 000m² and 25 000m², respectively. Based on the comparison of design, construction and monitoring between these two projects,a design idea on specially deep and big excavation is presented.     

Structures

Average annual electricity use per gross floor area is 236kWh/m²yr for offices and 366kWh/m²yr for hotels. HVAC and lighting account for 70–80% of total energy in fully air‐conditioned commercial buildings in Hong Kong and should be a priority for energy management programmes.     

A Life-Cycle Cost Comparison of Exit Stairs and Occupant Evacuation Elevators in Tall Buildings

Recent changes in the International Building Code (IBC) require a third exit stair for buildings in excess of 420 ft (128 m) high. Additionally, the new code provision allows for occupant evacuation elevators (OEE) to be used as an alternative to the third stair, provided the passenger elevator be protected in such a way to facilitate safe building evacuation. In this study, we evaluate the life-cycle costs of these alternative means of egress, using two prototypical building designs. Building ‘42F’ is a 42 floor, 504 ft (154 m) high building with a total floorspace of 1.68 million ft² (0.16 million m²). Building ‘75F’ is a 75 floor, 900 ft (274 m) high building with a total floorspace of 3.38 million ft² (0.31 million m²), including an 8403 ft² (781 m²) sky lobby. The life-cycle cost of the OEE is compared to two exit stair designs, differentiated by width: 44 in. (112 cm) and 66 in. (168 cm). The wider exit stair conforms with another change to the IBC that requires the increase in width of exit stairs by 50% in new sprinklered buildings. The results of the economic analysis demonstrate that: (1) an additional exit stair is a cost-effective alternative to the installation of OEE on a first-cost basis; and (2) OEE are a cost-effective alternative to the installation of an additional exit stair on a life-cycle cost basis when rental rates are moderate to high and when discount rates are moderate to low.     

龙口市浅层地温能潜力评价及经济环境效益分析

浅层地温能作为绿色新能源,近年来在越来越多的地区得到开发与应用,通过对龙口市主城区展开水文地质调查、地温场调查、现场热响应试验及热物性试验等工作,查明了工作区浅层地温能的赋存条件,得到了地埋管型地源热泵的开发利用潜力分区,并通过等效计算获得浅层地温能开发利用经济、环境效益价值。根据调查与计算分析可知：考虑土地利用系数时,(1)工作区地下水换热系统夏季可制冷面积1082.00×10⁴ m²,冬季可供暖688.55×10⁴ m²;地埋管换热系统夏季可制冷面积1573.43×10⁴ m²,冬季可供暖1677.81×10⁴ m²。(2)浅层地温能开发利用总能量为755.79×10⁴ GJ/a,折合标准煤15.06×10⁴ t/a,节煤量43.04×10⁴ t/a,热资源价值10543.51万元/a。(3)可减少排放氮氧化物、二氧化硫、二氧化碳、悬浮质粉尘、...     

Preserving Shipboard AFFF Fire Protection System Performance While Preventing Hydrogen Sulfide Formation

There is a very serious problem aboard US Navy ships from generation of toxic hydrogen sulfide (H₂S) in Aqueous Film-Forming Foam (AFFF) solutions used for shipboard fire protection. This is the result of the action of sulfate reducing bacteria (SRB) in mixtures of seawater and AFFF, which remain stagnant for significant time periods in shipboard fire protection system piping. Similar to microbial generation of H₂S in sewage, over time microbes present in seawater consume organic materials in the AFFF mixture and can deplete the dissolved oxygen. If the reduction-oxidation potential falls low enough, anaerobic action of the SRB on the sulfate present in seawater can then result in H₂S generation, reaching dangerous levels. The recommended ceiling for exposure to H₂S is only 10 ppm. If the microbes causing oxygen depletion and/or the SRB can be eliminated (or sufficiently minimized), the dangerous generation of H₂S would not occur. The Navy Technology Center for Safety and Survivability is participating in a research project for the Naval Sea Systems Command (NAVSEA) to evaluate several treatment modalities for their ability to inhibit H₂S formation in AFFF/seawater mixtures and for possible deleterious effects on AFFF performance. Various approaches have been considered employing laboratory evaluations (dynamic surface tension and Ross-Miles foamability), and 28 ft² (2.6 m²) pool fire extinguishment and burnback protection field tests (Military Standard MIL-F-24385F). The protocol selected for NAVSEA shipboard H₂S generation mitigation testing is a combination of a commercial broad-spectrum biocide with a molybdenum compound which is a specific inhibitor of SRB.