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Air Conditioning case study

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Air Conditioning case study

  1. 1. AIR CONDITIONING CASE STUDY
  2. 2. Ano 2005 Electric energy 803 MWh 233 tep Specific consumption 197 kgep/m2 CICA - Informatics Center The building CICA has three floors and the ground floor is the centre of informatics resources. The function of this building is mainly to ensure and make available all the informatics services for the FEUP community and to uphold its innovation and use. The cooling power installed in these spaces is not enough to remove the total load that occurs inside the building, which causes a high indoor air temperature leading to harmful situations, causing damages and reducing the performance of the informatics hardware. The main goal of this audit is to evaluate the correct cooling power, as function of the demand of the four zones showed on Figure 1. It is, also, necessary to verify the efficiency of air flow distribution inside the different spaces and the assessment of ventilation as it was proposed in earlier. The indoor air set point temperature will be object of concern in this studied case. If this value can be increased (i.e. increase set point temperature) lower energy consumption will be achieved without reducing the total performance of all systems. This building employs electric energy as a source of final energy. The following picture shows values for the energy consumption in the year of 2005, as well as for the specific consumption.
  3. 3. Design Details The HVAC system installed in below grade floor of CICA building is an all refrigerant system, where, all units work with R22 refrigerant. In D-102 and D- 104 rooms, there are ceiling splits with 5 kW of cooling power, connected to the condenser units installed in the building’s rooftop, Error! Reference source not found.. The rooms, D-101, D103 and D- 104 are equipped with close control units; one unit in the first two places and two units in the last one, Error! Reference source not found., an individual condensing outdoor unit is also located in the building rooftop. The Close control units allow humidity control inside the spaces. Schematic of the ventilation systems distribution illustrates the functionality of the close control units installed in the different zones where reheated /re-cooling air is supply by grids under the floor. Schematic of the condensers existing in the building rooftopSchematic of the close control Control Strategy The HVAC system works in continuous throughout the year where the indoor air set point temperature is 25ºC and the relative humidity is 50%. Each close control unit performs the specified set-point of the air conditioning space.
  4. 4. Problems • Actual HVAC system is not adjusted to the demand • The internal loads are higher than the installed HVAC system, causing the damage and reducing of the performance of the informatics hardware. • In summer the indoor comfort is more challenging Solutions – Major Modifications The solution proposed is, in energetic and environmental field, the most adjusted since it is a centralized system and has a higher efficiency. This solution also allows the power increase without major costs. The considered HVAC system can be defined as an air/water system. It will be composed by a cold-water central producer (chiller), located in the building covering, and by a cold water distribution net with two pipes, for supply and return. This circuit will supply the existing cooling coils in the independent Close Control units. These units are located inside the acclimatized spaces or, guarantee the indoor air quality. This system will also include the possibility of free-cool the spaces, given the adequate exterior air conditions. The following equipments form the proposed system: - Chiller with scroll compressor with 100 kW of cooling capacity; - Four Close Control units supplied with cold water which integrates system of humidification and electric resistance for heating; - Ventilation, piping and control system… As it was already referred, the treated air is supplied through the floor, and there aren’t any ducts to promote the air distribution. figure 6 shows an air outlet, which allows the treated air supply in to the zone. As shown, there are cables in the floor that difficult the air flow and do not allow a uniform air distribution. Thus, it was verified that the indoor air temperature in the different spaces are not homogeneous. it is possible to conclude that the equipment placed in the opposite side of the Close Control units, can easily reach temperatures about 34/36 ºC.
  5. 5. ‘Upside Down Townhouse’ Designer Demands Sustainability, Space-Saving features in Heat Pump System The Challenge: Jayna Cooper wanted to maximize her living space but the heating and cooling equipment would require setting aside scarce space to accommodate bulky HVAC ductwork. Daikin’s Solution: With Daikin’s 4-Port Multi-Split ductless system, Cooper regained use of valuable space and kept her commitment to sustainability with a system rated SEER 17.2 and HSPF 9.3. The 1,600-sq.-ft. home in Los Angeles designed and built by architect Jayna Cooper is a model of sustainability. It includes an energy-efficient, duct-free Daikin AC® 4-port Multi-Split system for heating and cooling. Application: Residential Location: Los Angeles, CA Cooper’s home has an open-loft design on the third floor, which includes the living, dining, kitchen and office areas. Two wall mounted units service the space, including one in the kitchen area, operated by individual wireless remote controllers. 1,600-sq.-ft. “upside down urban townhouse” is a model of efficiency, where the use of space is optimized and the living areas comfortable. If a conventional unitary ducted system were chosen, Architect would have to design a space with space for ductwork throughout the stacked house, winding through the kitchen cabinets and closet space. Solution to the problem. A duct free Daikin 4-port Multi-Split system that eliminated the need for ductwork, noisy outdoor compressors, or bulky window units was specified. Cooper’s home was recently featured in the prestigious magazine Architectural Record, recognized for its innovative design, which includes a third floor open loft with living, dining, kitchen, and office; a second floor for two bedrooms; a first floor dedicated to the driveway and carport; and fourth floor roof deck.
  6. 6. The Daikin system that serves the residence includes two unobtrusive CTXS12 wall- mounted indoor units located on opposite walls of the loft area and one CTXS09 indoor unit in each of the bedrooms. The compact 4MXS32 outdoor unit sits in the corner of the roof deck. The 32,000-Btu/h system has a SEER rating of 17.2, one of the highest in the industry, and an HSPF rating of 9.3. The compact 32,000- Btu/h outdoor unit sits in the corner of the home’s top-floor roof deck. It has a SEER rating of 17.2, one of the highest in the industry. The system features inverter technology, which delivers exactly the amount of heating or cooling needed to each zone of the home. The Daikin system based on its inverter variable speed compressor technology, which operates at required capacity, delivering exactly the cooling or heating needed to maintain the desired comfort condition while reducing energy consumption to one-third compared to normal on/ off units. The system avoids short start/stop cycling operation of the compressor, reducing costly current peaks, and minimizes temperature fluctuations.
  7. 7. 1) High efficiency VRV Sensible heat and latent heat are controlled separately with the combination of High efficiency VRV and DESICA. This enhances interior thermal comfort by individually controlling temperature and humidity. Drastic energy saving is realized by reducing wasteful energy use such as excessive cooling or heating. 2) Natural energy Water cooled VRV which is an under developing prototype is utilized for the entrance hall of TIC. This equipment achieves big energy saving thanks to the use of natural energy; - Utilization of geothermal heat for cooling / heating water - Collection / release of heat via solar heat collection / release panel Aims for a Net Zero Energy Building (ZEB), and 70% energy saving was achieved in 2015 by using various Daikin technologies. 100% energy saving is to be achieved by 2020. Air conditioning system study
  8. 8. 3) Solar power Solar panel with solar tracking system is adopted to TIC. It can chase sunlight and generate 1.3 times electricity greater than a general fixed type solar panel. In TIC total 300kW of electricity is generated by fixed type and tracking type. 4) Water mist spray Water mist spray system for outdoor units is installed to make the heat exchange efficiency higher. By spraying pulverized water droplets, moisturizing of heat exchanger is largely curtailed while the effect of water sprinkling is maintained.* This system is available in Japan only 5) Data analysis Demonstration experiment system adopted for further energy saving activities to achieve ZEB. Comfort and energy saving performance are evaluated by many sensors attached to the building. The analysis data is used for optimum control of not only air conditioning but also lighting, blind, and shades.
  9. 9. Comfort assessment Finely placed sensors monitor temp., humidity, CO2, human feeling & illuminance Energy saving assessment Individual monitoring of air conditioning, ventilation, lighting and office equipment. Total control of facility Following facilities are controlled comprehensively. - Air-conditioning and ventilation - Lighting : ON/OFF, Illuminance - Shades : Height, Angle Optimum air conditioning products for office and laboratory At TIC, 2 types of applications (Office and laboratory) are integrated in one building. For this reason, optimum A/C products and control for each application are needed. In the office area, the number of people differs substantially in accordance with the situation. Additionally the heat load varies greatly due to many glass windows. That’s why VRV, which can cope with different heat load of the space, are adopted. There are large space and many rooms in the laboratory area. Module type heat pump chiller and centrifugal chiller are adopted for the laboratory area. They are utilized for the air conditioning system and also providing cool water for experiment use. VRV is also adopted for the laboratory area and supports air conditioning. Chiller and VRV are managed and controlled all together by a central monitoring system.

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