Solar Oven Written - Lab Report Example

Lab Report on Solar Oven The major purpose for the lab was to create an excel spreadsheet that allows you to vary the input parameters for the solar oven project and to predict the inside oven temperature. At the beginning, the ambient temperature was 750c while internal temperature was 810c. The internal oven temperature was then measured at 5-minute intervals. In which case the resulting highest temperature reached was 1260c and the SOTD performance index was 3.23. Introduction Regardless of its specific form, solar oven is considered as a device able to transform solar energy into heat.

Internal temperature of the oven cavity normally starts to rise as soon as it is placed in the sun and afterwards reach a constant value known as thermal equilibrium. Consequently, an important activity is to vary the input parameters for the solar oven project and to predict the maximum oven temperature which gives thermal equilibrium. To the developing world, solar oven is an appealing concept given the nature of the energy source. The popularity is attributed to the way energy is harnessed without involving in burning fuels because of it is a renewable source.

it’s safe, smoke free which means its eco-friendly, and costs nothing. This makes solar even more reliable because it is plenty in nature and does not require long procedures for obtaining. Design theory and analytical modelAt thermal equilibrium, basic thermodynamics states that the energy flowing into the oven must be equally balanced by the energy that flows out of the oven and that the power absorbed by the oven equals the power that leaves out of the oven (Sage, 237). This is as illustrated by the following: EOUT = EINPout = PabsorbedGoal is to write down equations for both Pout and Pabsorbed, as a function of the design and material properties of our actual oven.

Setting these equations equal, we will be able to solve for the internal temperature of the oven in terms of all of these material properties.Power out:An equation that is more suitable for our solar oven includes two separate heat-loss terms: a term describing how much heat flows out of the sides and bottom of the oven, and a term that describes how much heat is lost out of the windowPout = (Usb* Asb +U w*Aw) (Tio – T ambient)Whereby: Usb = the overall heat transfer coefficient for the sides and bottom of the interior oven chamber Asb= the total area of the sides and bottom of the interior oven chamber Uw= the overall heat transfer coefficient for the window Aw= the area of the window Tio = the temperature in the interior chamber of the oven Tambient = the temperature of the air surrounding the oven (the outdoor temperature on testing days)It is worth noting that in this equation, Asb, Aw, Usb, Uw are all design variables: Asb is set by the dimensions you pick for the sides and bottom of the interior chamber.

Aw is set by the dimensions you pick for the window. Usb is determined by the material you pick for the walls and insulation. Uw is determined by the material you pick for the window.For power absorbed: Pabsorbed = I0AW* τ*a*sin(θs + β) τ= the optical transmission coefficient of the window material (0 ≤ τ ≥1)a= the absorption coefficient of the cavity walls (0 ≤ a ≥1)I0=incident solar power density, in watts/meter2Overall equation for the designHence from Pout= Pabsorbed, the internal temperature will reach maximum where (Usb* Asb +U w*Aw) (Tio – T ambient) = I0AW* τ*a*sin(θs + β)Hence overall equation for the design:TIO =Tambient + Constant in this equation Io, θs, and TambientDesign variables in this equation: Aw, τ, a, β, Usb, Asb, and UwDesign requirements In this case, a proper design is the use of reflectors, which can perform in increasing the internal temperature of the oven.

The reflector increases the temperature through delivering more sunlight to the window and into the cavity of the oven. The significant design constraint considered for the design is that the used reflectors should have flat surfaces and not, in any way, curved surfaces. This is because curved surfaces are known to focus sunlight at the window, thereby increasing the internal temperature (I0) to above 1000 W/m2 based on orders of magnitude (Sage 237). Even though the result from this are impressive, they are dangerous and hazardous given that the oven may end up in flames thereby interfering with the desired performance index.

Work cited Sage, Andrew P, and William B. Rouse. Handbook of Systems Engineering and Management. Hoboken, N.J: John Wiley & Sons, 2009. Print.