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The quoted price to install the system was 150000 the

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Unformatted text preview: quoted price to install the system was ∼$150,000. The contractor also provided an estimate of the annual energy cost to cool the fresh-air of ∼ $4,400. • The motion to proceed with the quote did not pass. • The residents have asked UW Engineering to suggest alternative solutions. In particular, the residents have expressed interest in “energy efficient” options. contractor proposed new cooling system Roof-Mounted Condenser Unit Cool Elec Heat Refrigerant Lines Air Intake Fresh-Air Duct Fresh-Air Unit Roof Corridor / Residential Suite exfiltration/exhaust (to outdoors) 15th Floor Corridor /c Residential Suite exfiltration/exhaust (to outdoors) 14th Floor Corridor /c 13th Floor To other floors Residential Suite exfiltration/exhaust (to outdoors) Bauer Lofts -- 12th Floor Layout 12th Floor Layout – “Common Areas” Indicated 12th Floor Layout Residential Suite Residential Suite Residential Suite Residential Suite Residential Suite Residential Suite Residential Suite Residential Suite Residential Suite Residential Suite Residential Suite Residential Suite Residential Suite 12th Floor Layout – Common Areas stairs stairs elevators electrical trash corridor air duct air duct Elec Heat Heat 5500 cfm Air Intake Elec 7000 cfm Fresh-Air Unit Air Intake Fresh-Air Unit Roof • • heating sections are natural-gas fired fan motors are both 5 hp 15th Floor 5500 cfm + 7000 cfm 12,500 cfm 14th Floor 13th Floor To other floors continuous ventilation rate (8760 hrs/year) Additional Info • In-Suite Heating and Cooling is provided by a waterloop heat-pump system. – Each suite has a heat-pump connected to a shared water-loop. (Some larger suites have more than one heat pump.) • If a suite needs heat, the heat-pump absorbs heat from the loop and delivers it to the suite. • If a suite need cooling, the heat-pump absorbs heat from the suite and rejects it to the loop. • If the water-loop temperature drops, natural-gas fired boilers provide heat addition. • If the water-loop temperature rises, a fluid-cooling (i.e. cooling-tower) provides heat rejection. Simplified Schematic Representation of a Water-Loop Heat Pump System cooling tower return pipe supply pipe boiler ZONE 1 ZONE 2 T Zones terminal units: water-to-air heat pumps Note: Bauer Lofts has approximately 250 heat-pumps. T Partial Schematic Diagram of the Water-Loop Heat Pump System Partial Info on the Contractor Proposal: Estimate of Annual Cooling Electricity Provided by Contractor: Example Refrigerant and Air Temperatures for a “DX Air Conditioner” Condenser Coil Tair,outdoor = 35°C Outdoor Air Tcond = 52°C electricity expansion valve Tevap = 4°C Indoor Air Tair,in = 24°C compressor Tair,out = 13°C Evaporator Coil Schematic Depiction of “Water-to-Air” Heat Pump Reversible vapor compression refrigeration cycle COMPRESSOR REVERSING VALVE fan + motor EXPANSION VALVE air water REFRIGERANT-TO-WATER HEAT EXCHANGER REFRIGERANT-TO-AIR HEAT EXCHANGER Building Energy Performance – Spring 2012 - Topic 21 Aspects of Building Energy Codes & Green Building Rating Systems Building Codes • Building Codes are typically used to define a minimum acceptable level of “good practice” for certain aspects of building design and construction. They are typically focused on objectives such as: • • • • Health Safety Accessibility Fire & Structural Protection • To a certain degree, a building code may be thought of a describing “the worst you can legally get away with.” Building Energy Codes • It is becoming more common in North America that building codes (e.g. the Ontario Building Code) include provisions that cover aspects affecting building energy performance. • These typically describe requirements considered to be minimum “good practice” for aspects that have an important impact on its energy use, such as: – Thermal resistance of walls and roofs – Maximum window-to-wall ratio – Minimum rated efficiencies of HVAC equipment – Maximum allowable lighting power density Some building energy codes/standards commonly used in Canada: • ASHRAE Standard 90.1 – Energy Standard for Buildings except Low-Rise Residential Buildings, (“ASHRAE 90.1)” – Under “continuous maintenance”, a new version released approximately every 3 years – Past releases include: 1999, 2001, 2004, 2007, 2010 – Widely used across North America • Model National Energy Code of Canada for Buildings 1997 (“MNECB”) • National Energy Code of Canada for Buildings 2011 (“NECB”) Note: ASHRAE 90.1, MNECB, and NECB are codes/standards that are intended to be applied to “Buildings” rather than to “Houses” (i.e. low-rise residential). There are other codes/standards intended for application to houses. Overview of ASHRAE 90.1 and MNECB Both ASHRAE 90.1 and MNECB contain sections that list requirements for: • Building Envelope • Lighting • Heating, Ventilation, & Air-Conditioning Systems • Service Water Heating Systems • Electrical Power Both codes list requirem...
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This note was uploaded on 10/04/2012 for the course ME 760 taught by Professor Davidmather during the Spring '12 term at Waterloo.

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