A 2 x 2 m flat plate solar collector for domestic hot water heating is shown in the figure. The incident solar radiation on the glass cover, which transmits 90% of the incident flux, is 750 W/m2. Water flows through the tubes soldered to the backside of the absorber plate, entering at a temperature of 25°C. The temperature of the glass cover is 27°C, and it radiates heat with an emissivity of 0.92 to the sky at –50°C. Additionally, the glass cover losses heat by convection to air at 20°C flowing over its surface at 30 km/h. Assume that the radiation heat transfer between the absorber plate and glass cover and the heat transfer through the back and sides of the collector is negligible.

Calculate the decrease in heat loss in kilowatt-hours per day when a 1.2 m x 2.1 m uncoated single-pane window is replaced with a double-glazed window with a low-e coating and argon fill (a relatively common configuration for current win- dows). The inside temperature is a constant 20°C, and the outside temperature is a constant -5°C.

Determine the luminous efficacy of the following lamps having comparable illumination outputs:a. A 300 W incandescent lamp that emits 5820 lmb. Two 32 W linear fluorescent lamps that emit 2950 lm per lamp in a luminaire that consumes 70 W including the ballastsc. A 70 W metal halide lamp that consumes 88 W, including the ballast and emits 5500 lm

Calculate the power radiated by a woodstove of dimensions 65 cm high by 55 cm deep by 85 cm wide with a surface temperature of 120°C. Assume that heat is radiated from all surfaces of the stove and that the stove has an emissivity of 1. Note that woodstoves are painted black because black surfaces have high absorptance, and objects with high absorptance also have high emissivity.

A spring-loaded piston-cylinder device contains 1.5 kg of carbon dioxide. This system is heated from 200 kPa and 25 °C to 1200 kPa and 300°C. Determine the total heat transfer to and work produced by this system.

An ESP is to he designed to treat 9000 m3/min of gas to remove particles at 99.8% efficiency. Using Figure 5.10, estimate the required corona power in kW.

22   A power plant has efficiency of 30 % as compared to Fuel Cell power plants. This power plant can be .......................................... a. Geothermal Power Plant b. Wind Power Plant c. Thermal Power Plants d. Biomass Power Plant

4. An incandescent lamp has a tungsten filament whose resistance is 96 ohm at its operating temperature of 2900°C. Calculate the filament resistance when the lamp is disconnected from the electric source under which conditions the temperature is 24°C.