1. Engineering
  2. Mechanical Engineering
  3. please work problem 3 and 4 so i can see...

Question: please work problem 3 and 4 so i can see...

Question details
Please work problem 3 and 4 so I can see what I am doing wrong. Thank you.
A sauna is a heated well-insulated room that is used for short periods of time. When in use, it heated to high temperatures, on the order of 90°C or 190°F. The most common construction technique uses a laver of wood to form the inside layer of the walls. An idealized version of the construction as shown in Figure I below. (And this construction will be the same for the floor and roof. The sauna is built on piles, so it is exposed on all sides to the outdoor air.) Sauna 1 Western red cedar Inside convection coefficient Fiberglass batt Insulation, 5.5 thick % plywood Outside convection coefficient Figure 1 Idealized sauna construction The following simplifications and details apply: Thermal properties for the three layers are in Table 1 below. . The sauna has inside dimensions of 7 high x 107x 6·The total inside surface area of the sauna is 540 square feet. You may use the inside surface area for all heat loss calculations. Table 1 Layer Descriptions Thickness Density Conductivity Specific heat (in) (lb/t (Btu in/(h ft F) Btu/(lbmF) Layer 2 plywood Fiberglass batt insulation 0.5 5.5 2 29 0.5 0.63 0.30 0.45 0.20 Western red cedar 1.5 0.85 0.39
For the sauna problems, give answers in Btu, Btu/h as appropriate and state your units Show your work for each problem, but put the answers in the boxes 3. If the sauna room is to be heated up in 45 minutes from 70°F to 190° F, what is the heat input rate required to heat the western red cedar layer and benches mad of western red cedar? The volume of the western red cedar layer is 67.5 ft3 and the volume of the benches (also made from western red cedar) is 5 ft Answer: sr9523 Units: uthr 4. If the flow rate of ventilation air coming into the sauna is 20 CFM, witha temperature of 20°F, a specific volume of 12 ft/lb, specific heat of 0.24 Btu/(lb °F),what is the heat input required to heat the ventilation air to 190°F? its: Answer: y030 -
Solution by an expert tutor
Blurred Solution
This question has been solved
Subscribe to see this solution