HVAC design sample

University of Toronto Faculty of Applied Science and Engineering Department of Mechanical and Industrial Engineering

MIE1224H HEATING, VENTILATING, AND AIR CONDITIONING Final Project, 2015

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Consider the two-bedroom unit in the 5  floor of a 10 story residential tower located in your designated city . The building is located close to a large artificial pond and the common reflective exterior surface can be considered as water. The location and orientation of the building and the unit in question are shown in figure 1. For the design condition, it is safe to use the clear sky model with 23 km visibility range.

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Figure 1 Floor plan of the 5  floor showing the orientation of the building and the location of the unit in question

The central mechanical ventilation system of the building maintains a constant overpressure ∆ of 30 Pa at 20˚C in the corridors. Except for the unit entrance door and windows, the

rest of the unit is air tight. All doors and windows are weather-stripped and frames are caulked. Windows are clear out, clear in double glazed with 3 mm nominal thickness. All the perimeter walls are composed of 8” H.W. concrete, 2” insulation, and 1” of dry wall with light exterior

color. Interior partitions are standard dry wall. Dimensions and types are shown in figure 2 along with the layout of the unit. In order to find heating and cooling loads, effect of lights can be neglected. Also, for simplicity, you can ignore the transient effect of occupants’ presence. How ever, for peak load calculations,

assume there are 4 people in the unit, with light activity during the day and sleeping at night. Appliances are also used for cocking from 10:00 am to 1:00 pm. You can make realistic assumptions for appliances power ratings. You can also neglect the heat transfer between units and corridors and use CLTD/CLF method for your calculations. The building has a central plant that produces chilled water at 5°C and hot water at 70°C, transferred to each unit via a central piping system. For residential units of small size, it is customary to treat the whole unit as a single zone with 1 thermostat control. In this project we are focusing on the peak load design only and the goal is to design a fixed air volume system to service the unit in question. The complete air handling package must be small enough to fit in the designated space in bedroom 2. You are required to select all the necessary components from available manufacturer’s data based on your load calculations. Please note that this is a

design problem which allows you to make reasonable assumptions. Your report must contain the following items and clear explanation on how you have done your calculations and why you have made your assumptions: a) A psychometric chart specially plotted for the city assigned to you b) A sun path diagram for the location of the building c) Two Sol-Air Temperature plots for the peak heating and cooling days d) All the necessary steps for cooling and heating load calculations plus all the tables and charts you have used doing so e) Calculations of volumetric air flow rate requirements f) Air filter, cooling and heating coils selection g) Humidifier selection if necessary h) Duct design and sizing, pressure drop calculations, and fan selection Your design must also satisfy health, comfort, and noise level requirements. At the end of the report, please conclude your design by commenting on the efficiency of the system, and ways to improve it.

Figure 2 Unit layout (the drawing is to scale and dimensions can be extracted from the known bedroom sizes)