ARCH 447 Assignment 2

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School

McGill University *

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Course

447

Subject

Mechanical Engineering

Date

Jan 9, 2024

Type

docx

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Uploaded by ChefAnteater4058

Assignment 2 Analysis: Change made Impacts Significan ce Change made Impacts Significanc e Change made Impacts Significanc e Increase the per person ventilatio n rate from 15 l/s/pp to 16 l/s/pp The ventilati on leakiness increase d from 5437 W/K to 5799W/K and the free running balance point temperat ure decrease d from 5.3 to 5.1C Increasing the ventilation rate a little allows for further heat exchanges with the outdoor environme nt during the summer, allowing for a slightly more balanced and comfortab le temperatu re, without increasing heat losses too much during the winter. Increase the glazing U-value from 0.75 to 0.80. Conductio n leakiness decreased from 1135 W/K to 1176 W/K. Ventilatio n % went up from 84% to 83%. Free running balance point stayed constant at 5.1 The glazing U-value is increased to 0.8 which is a more utilized triple glazing in the industry. This will create more heat exchanges from glazing areas which is however going to be compensat ed for by the new mechanical system. Glazing ratio increas ed from 0.16 to 0.1675 Conductio n leakiness slightly increases from 1139 W/K to 1135 W/K. Heated balance point constant at 9.2. Slightly increasing the glazing ratio reduces the heat lost through the opaque envelope. The solar heat gain is also increased. Social Spaces Quiet Spaces Back of House Spaces Total Notes Occupants 109 99 86 294 Number of occupants in all spaces according to ventilation design standards Ventilation Leakiness (W/K) 2149 1952 1698 5799 Ventilation leakiness estimated from volumetric heat capacity of air multiplied by ventilation rate in all spaces Conductio n Leakiness (W/K) - - - 1176 Leakiness from glazing and envelope, calculated using U- values Heat Gains (W) 13080 11880 10320 35280 Benchmark heat gain estimate per person (120W/person) multiplied by number of

occupants in all spaces Free running Balance Point (dT) - - - 5.1 Total heat gains over sum of ventilation leakiness and conduction leakiness Heat Recovery (C) 752 683 594 2030 Ventilation leakiness multiplied by the inverse of the heat recovery efficiency Suppleme ntary Floor Heating (W) - - - 28700 Total floor area multiplied by supplementary floor heating rate Performance variables Outdoor air ventilation rate (l/s/person) U-glazing (W/m2/K) Heat recovery efficiency U-envelope (W/m2/K) Glazing ratio Casual heat gains (W/person) Supplementary floor heating (W/m2) 15 0.8 0.65 0.12 0.1675 120 10 Natural ventilation possible in May, June, July, August and September Mixed-mode ventilation possible in April and October Artificial ventilation possible in January, February, March, November, and December

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DOAS components: DOAS with Recovery Wheel : Responsible for supplying a controlled and conditioned volume of outside air to the building and helps to exchange heat and moisture between outgoing and incoming air, improving energy efficiency by pre-conditioning the outdoor air. It was placed on the roof because its role implies it must be outside with easy access for maintenance and above the mechanical room to reduce the amount of ducking and to avoid having it over occupied spaces to minimize noise impact. Air-Cooled Chillers: Uses the principles of refrigeration to remove heat from the building’s interior. Water is cooled by the chillers, which is then circulated through the building’s chilled water piping system. The chillers were placed in the mechanical for easy maintenance access and to minimize noise impact on occupied spaces. Chilled Water Piping: Distributes chilled water from the chiller to various fan coil units throughout the building. The chilled water absorbs heat from the building’s air when it passes through the fan coil units, and thus cools indoor spaces. It is located in the interstitial spaces between floors throughout the building. Fan Coil Units: Coil units consist of a fan, a coil and controls, and are placed in different rooms in the building, in a concealed location. During cooling, the chilled water coil cools the air passing through it and the fan distributes the cooled air into the rooms. During heating, air is warmed with a hot water coil. Heating Hot Water Piping: Carries hot water from the boiler to the fan coil units. They are distributed through the service shafts. Boiler: Provides a heat source for the heating hot water used in the fan coil units. It is located in the mechanical room for easy access for maintenance, for safety and to minimize noise impact.

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