Functional Requirements
This section provides the functional requirements, the tasks and behaviours that the software is expected to complete.
Input-Values: Input the values from Tab:ReqInputs, which define the tank parameters, material properties, and initial conditions.
Find-Mass: Use the inputs in FR:Input-Values to find the masses needed for IM:eBalanceOnWtr, IM:eBalanceOnPCM, IM:heatEInWtr, and IM:heatEInPCM, using DD:waterMass, DD:waterVolume_pcm, and DD:tankVolume.
Check-Input-with-Physical_Constraints: Verify that the inputs satisfy the required physical constraints.
Output-Input-Derived-Values: Output the input values and derived values in the following list: the values (from FR:Input-Values), the masses (from FR:Find-Mass), \({τ_{\text{W}}}\) (from DD:balanceDecayRate), \(η\) (from DD:balanceDecayTime), \({{τ_{\text{P}}}^{\text{S}}}\) (from DD:balanceSolidPCM), and \({{τ_{\text{P}}}^{\text{L}}}\) (from DD:balanceLiquidPCM).
Calculate-Values: Calculate the following values: \({T_{\text{W}}}\)(\(t\)) (from IM:eBalanceOnWtr), \({T_{\text{P}}}\)(\(t\)) (from IM:eBalanceOnPCM), \({E_{\text{W}}}\)(\(t\)) (from IM:heatEInWtr), and \({E_{\text{P}}}\)(\(t\)) (from IM:heatEInPCM).
Verify-Energy-Output-Follow-Conservation-of-Energy: Verify that the energy outputs (\({E_{\text{W}}}\)(\(t\)) and \({E_{\text{P}}}\)(\(t\))) follow the law of conservation of energy, as outlined in Properties of a Correct Solution, with relative error no greater than \({C_{\text{tol}}}\).
Calculate-PCM-Melt-Begin-Time: Calculate and output the time at which the PCM begins to melt \({{t_{\text{melt}}}^{\text{init}}}\) (from IM:eBalanceOnPCM).
Calculate-PCM-Melt-End-Time: Calculate and output the time at which the PCM stops melting \({{t_{\text{melt}}}^{\text{final}}}\) (from IM:eBalanceOnPCM).
Output-Values: Output \({T_{\text{W}}}\)(\(t\)) (from IM:eBalanceOnWtr), \({T_{\text{P}}}\)(\(t\)) (from IM:eBalanceOnPCM), \({E_{\text{W}}}\)(\(t\)) (from IM:heatEInWtr), and \({E_{\text{P}}}\)(\(t\)) (from IM:heatEInPCM).
| Symbol | Description | Units |
|---|---|---|
| \({A_{\text{C}}}\) | Heating coil surface area | \({\text{m}^{2}}\) |
| \({A_{\text{P}}}\) | Phase change material surface area | \({\text{m}^{2}}\) |
| \({A_{\text{tol}}}\) | Absolute tolerance | – |
| \({{C_{\text{P}}}^{\text{L}}}\) | Specific heat capacity of PCM as a liquid | \(\frac{\text{J}}{\text{kg}{}^{\circ}\text{C}}\) |
| \({{C_{\text{P}}}^{\text{S}}}\) | Specific heat capacity of PCM as a solid | \(\frac{\text{J}}{\text{kg}{}^{\circ}\text{C}}\) |
| \({C_{\text{W}}}\) | Specific heat capacity of water | \(\frac{\text{J}}{\text{kg}{}^{\circ}\text{C}}\) |
| \(D\) | Diameter of tank | \({\text{m}}\) |
| \({H_{\text{f}}}\) | Specific latent heat of fusion | \(\frac{\text{J}}{\text{kg}}\) |
| \({h_{\text{C}}}\) | Convective heat transfer coefficient between coil and water | \(\frac{\text{W}}{\text{m}^{2}{}^{\circ}\text{C}}\) |
| \({h_{\text{P}}}\) | Convective heat transfer coefficient between PCM and water | \(\frac{\text{W}}{\text{m}^{2}{}^{\circ}\text{C}}\) |
| \(L\) | Length of tank | \({\text{m}}\) |
| \({R_{\text{tol}}}\) | Relative tolerance | – |
| \({T_{\text{C}}}\) | Temperature of the heating coil | \({{}^{\circ}\text{C}}\) |
| \({T_{\text{init}}}\) | Initial temperature | \({{}^{\circ}\text{C}}\) |
| \({{T_{\text{melt}}}^{\text{P}}}\) | Melting point temperature for PCM | \({{}^{\circ}\text{C}}\) |
| \({t_{\text{final}}}\) | Final time | \({\text{s}}\) |
| \({t_{\text{step}}}\) | Time step for simulation | \({\text{s}}\) |
| \({V_{\text{P}}}\) | Volume of PCM | \({\text{m}^{3}}\) |
| \({ρ_{\text{P}}}\) | Density of PCM | \(\frac{\text{kg}}{\text{m}^{3}}\) |
| \({ρ_{\text{W}}}\) | Density of water | \(\frac{\text{kg}}{\text{m}^{3}}\) |
Required Inputs following FR:Input-Values