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Industrial halls are characterized with their rectangular shape and relatively simple construction, as contrasted with office buildings with similar floor area. Industrial halls are usually subject to high energy demand due to the many manufacturing processes, lighting, and the corresponding amount spent on space conditioning. Thermal comfort is seldom a concern for industrial halls. By contrast, saving in energy consumption for lighting and space conditioning is a big issue since even the modest percentage change in energy consumption could be translated into a large monetary sum. With relatively loose requirement in space conditioning, and comparatively high internal heat gain; the approach in industrial hall design is quite different from that of office building. In fact, what poses to be an energy efficient design for office buildings might not be appropriate for high internal heat gain halls. The simplicity in the building geometry and the construction method allow the investigation of energy demand for space conditioning to be limited to a few number of demand side parameters (e.g. insulation value of walls); in which, change in values in some of the parameters presents a significant impact on the overall energy demand. This paper investigates the impact of varying different demand side parameters on the energy demand for space conditioning and lighting for a typical industrial hall. Through building energy simulation, such impact can be investigated; and by applying optimization, the configurations of the most optimal combinations of parameters with the lowest energy demand can be identified. The result indicates that the energy demand of the least efficient configuration can be more than double of that of the optimized design solution. This paper will also explore green building assessment systems such as LEED, in terms of energy performance, with the studied industrial hall as an example. The huge energy saving brought by the optimized design solution over the baseline building of LEED suggests that there might be a potential deficiency of LEED rating system at its current state as it applies to industrial halls. [ABSTRACT FROM AUTHOR]

This paper presents a new boiler model for dynamic simulations with the aim of an easy parameterization. First, the paper gives an extensive literature review to show the need for a new boiler model. This new boiler model is partly based on existing models as well as new aspects particularly for the dynamic representation. The main goal was as detailed as possible a representation of the dynamic behavior of a boiler on the basis of product data available in Europe. Several steady-state and dynamic measurements were made to validate the model. The measurements confirm the basic features of the model. However, they also show that a parameterization with only manufacturer data resulting from standard test procedures may lead to inaccurate results and thus indicate the need for a few more test sequences to be added to the standard tests. [ABSTRACT FROM AUTHOR]

Why do some customers experience gas leaks in air conditioning and refrigeration units before ten years of usage? Context is required to answer such a question. Consensus standards (ASME B31.5 [2007], ASTM B280 [2008], ASME B 16.22 [2001]) governing the production and use of copper tube and fittings deem most of these products insufficient to meet the higher operating temperature and pressure requirements of R-410A and other refrigerants. Though these standards appear to err on the conservative side, data taken from refrigeration and air-conditioning products seem to suggest that equipment manufacturers (OEMs) overestimate the performance of materials. For example, according to ASME B16.22, a 3/8 in. (9.5 mm) copper fitting with a mininum wall thickness of 0.026 in. (0.660 mm) is rated at 660 psi (4.55 MPa) at 150°F (66°C). However, data taken from OEM (R-410A) products show internal wall thicknesses as low as 0.009 in. (0.229 mm) in some failed units. The standard calculation for a wall of 0.009 in. (0.229 mm) would result in an allowable operating pressure of less than 300 psi (2.07 MPa). Where then is the discrepancy? The purpose of this paper has four parts: 1. Baseline the critical material properties, in addition to wall thickness and burst pressure, necessary to meet the higher pressure and temperature requirements. 2. Confirm the manufacturing process parameters that ensure the best material properties. 3. Provide an accurate, performance-based (empirical) method to calculate maximum operating pressures for annealed copper tube and fittings. 4. Validate the improved material properties through accelerated life test equivalent to 30 years in an R-410A system. Four different types of tests were conducted to determine the long-term effects of increased pressure and temperature on air conditioning and refrigeration copper tube and fittings. The tube and fittings were produced with a proprietary manufacturing process designed to eliminate fatigue failure while minimizing deformation during strain hardening. Parameter changes in the casting, drawing, annealing, and forming processes for 7/8 in. (22.2 mm) to 21/8 in. (54.0 mm) diameters enabled the tube and fitting assemblies to strain harden (without hydro forming) and withstand significantly higher pressures at increased temperatures. The four tests are as follows: 1. Hydrostatic pressure test with a different assembly at each pressure and temperature setting (hoop strain): Pressures were set at 635 psi (4.4 MPa), 800 psi (5.5 MPa), 1000 psi (6.9 MPa), and 1500 psi (10.3 MPa) with temperatures set at 68°F (20°C), 180°F (82°C), and 250°F (121°C). 2. Hydrostatic pressure test using a single assembly per temperature (hoop strain hardening): Temperatures were set at 68°F (20°C), 180°F (82°C), and 250°F (121°C). At each temperature, pressures were set at 635 psi (4.4 MPa), 800 psi (5.5 MPa), 1000 psi (6.9 MPa), and 1500 psi (10.3 MPa). Measurements of changes in length and diameter of tube and fittings were taken at each pressure level. 3. Fatigue Test at 180°F (82°C) and 650 psi (4.48 MPa) for 1000; 5000; 10,000; 20,000; and 50,000 cycles. Each cycle started at 100 psi (689 kPa), pulsed to 650 psi (4.48 MPa), and repeated every 4 seconds. Measurements of changes in length and diameter of tube and fittings were taken at each increment of cycles. 4. Accelerated life test using a heat pump fitted with a line set assembly with sizes from 7/8 in. (22.2 mm) to 2-1/8 in. (54.0 mm). The heat pump was modified for a 5-minute heating and cooling cycle (2.5 minutes cooling and 2.5 minutes heating). Measurements of changes in length and diameter of tube and fittings were taken at 20; 379; 900; 3200; 5700; 8740; 13,980; and 18,060 cycles, providing an accelerated life estimate of approximately 32+ years. At completion of testing, no failures were observed in the proprietary material. One failure was observed internal to the heat pump system utilized in the testing. This failure is attributed to the very thin wall inner-groove copper tubing. [ABSTRACT FROM AUTHOR]