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Facilities Larson Building Systems Laboratory The Larson Building Systems Laboratory is a unique facility in the HVAC industry. It is used for educational and research purposes and is designed for dynamic testing of complete and full-scale commercial HVAC and building systems. The facility consists of a full-size commercial HVAC system, four representative commercial building zones, a system for producing repeatable and controllable loads on the HVAC system, and sophisticated data acquisition and control systems. Activities at the Laboratory include evaluation and testing of control algorithms and hardware for HVAC components and systems, interactions between multiple control functions of HVAC systems, the dynamic interactions between building thermal response and HVAC system controls, ventilation control for indoor air quality, and HVAC system diagnostics. Full-Scale Zones Realistic building loads are represented using a configurable, typical building zone, which can be physically separated into 2 full-scale zones, each approximately 600 ft2 (60 m2). The shell of the large zone is constructed to provide R-50 insulation in the walls and roof to effectively isolate the zone from the ambient lab conditions. The modular wall used for separating the zones is rated at R-50. Each zone has its own fan-powered mixing box rated at 1200 cfm (567 L/s). Cooling loads are introduced into these zones using electric base-board heaters capable of 30,000 Btu/hr (9 kW) per zone, while heating loads are introduced using a radiant wall system (currently available in one full-scale zone). The two zones can also be used as environmental chambers. Zone Simulators Two additional building zones can be represented by zone simulators, in parallel with the full-scale zones. The simulators are used to impose programmable loads on the HVAC system and to provide "base-loading" on the system. The zone simulators are, essentially, expanded duct sections with cooling coils rated at 60,0000 Btu/hr (18 kW), electric heating coils rated at 80,000 Btu/hr (23 kW), and steam injection rated at 50 lb/hr (23 kg/hr) of low-pressure steam. Each of the zone simulators can simulate up to 3000-4000 sq. ft. of conditioned space with mixing boxes rated at 4000 cfm (189 L/s). Outside Air Conditioning Station The HVAC system is configured to mix outdoor air with return air from the building zones. An outdoor air conditioning station (OACS) is used to precondition the actual outdoor air before mixing at the main air-handler, allowing simulation of a wide range of climate conditions. The outside-air conditioning station contains an electric preheat coil, an evaporative cooler, a cooling coil, an electric reheat coil, and steam injectors. In addition, there are two face/bypass dampers which allow the proper mixing of airstreams to generate the desired temperature and humidity profile. The fan in this air handling unit is run from a variable frequency drive. The fan speed is controlled to maintain atmospheric pressure at the inlet louvers to the main air-handling unit. Main Air-Handling Unit The main air-handling unit mixes the simulated outdoor air with return air from the building zones and conditions the air to desired supply air conditions. The unit contains both chilled and hot water coils rated at 240,000 Btu/hr (70 kW) and 150,000 Btu/hr (44 kW), respectively. A variable frequency drive on the fan allows for easy control of the downstream duct static pressure. An axial vane return fan will either exhaust air from the zones or recirculate it back to the main air-handling unit. The return fan is also controlled using a variable frequency drive. Chiller and Ice Storage The chiller is rated at 75 tons (264 kW) cooling capacity and is comprised of two screw-type compressors. Continuous capacity control is provided to 10% of rated capacity. The chiller, a 3 hp (2.2 kW) constant volume pump, and a 190 ton-hour (668 kWh) ice storage tank are incorporated into a primary loop. A separate constant volume 3 hp (2.2 kW) pump circulates water through a secondary loop to the zone simulators and the two air-handling units. The chilled water loop contains a 25% glycol brine and allows the primary loop to operate at temperatures as low as 23 deg. F (-5 deg C). Boiler A 150,000 Btu/hr (44 kW) electric hydronic boiler provides hot water to a heating coil in the main air-handling unit (the only HW coil in the lab). Typical temperatures in this loop are around 122 deg. F (50 deg. C). Control and Data Acquisition The entire laboratory is under the control of a distributed direct digital control and data acquisition system, manufactured and donated by Automated Logic Corporation in 1997. The state-of-the-art system will be upgraded by Automated Logic to native BACnet trade; in early 1998. The hardware and software of the system have been configured to allow flexible control of all laboratory systems. (The system was actually installed and configured as part of a class project by a group of graduate and undergraduate students, shown in the photo.) Sensor and actuator signal are industry-standard 4-20 mA, though a wide range of input and output types are supported. The system is well-suited to exploration of unique control algorithms, including advanced local loop control and intelligent supervisory strategies.
Over the years, the Larson Laboratory has been the fortunate recipient of many equipment donations. Without these generations gifts, the Laboratory could not provide state-of-the-art equipment for learning and research. The following is a list of significant donors: Automated Logic Corporation
The Lighting lab is a learning and research space for lighting students in Architectural Engineering and Building Systems. The lab has a dynamic ceiling such that the height can be adjusted through wallbox control gear. This allows for a wide range of academic and research exploration. Although the lab has full wall south facing windows, there are blackout curtains installed to eliminate external light when it is undesirable as with certain types of research projects. In addition, this lab houses a goniophotometer. This apparatus is used to measure the intensity of light leaving a luminaire at various vertical and horizontal angles. From this information, the photometric light distribution of the luminaire is derived, and quantities such as total lumen output, luminaire luminance, zonal lumen summary and other information that is included in a photometric report can be computed. Furthermore, a moveable lighting station that includes low voltage track and various track luminaires is in the lab to compare track head types as well as the distribution of different types of reflector lamps. Other handheld illumination measurement equipment is available as well, including: illuminance meters, luminance meters, chromaticity meters, and other light detection devices. Also, there is a variety of lamp, socket, ballast, and luminaire samples for use in mock-ups, luminaire design exercises, and research projects. In addition to the main lab space there is studio space next to the main lab. This space is used primarily for lighting research. The lab has an extensive aluminum open ceiling grid that allows for quick electrical and physical connection of light sources and luminaires for research. The purpose of this lab is to provide an independent space for research on such topics as daylighting, light spectrum optimization, and psychological aspects of lighting.
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