﻿ 20-sim webhelp > Library > Iconic Diagrams > Thermal > Components > heatcapacity

# heatcapacity

Library

Iconic Diagrams\Mechanical\Thermal\Components

## Use

Domains: Continuous. Size: 1-D. Kind: Iconic Diagrams (Pseudothermal).

## Description

This is a general model for the heat storage in a specific material. A constant temperature distribution in the material is assumed and a constant heat capacity:

E = int(p.dQ) + C*T0;

p.T = E/C;

T0 is the initial temperature of the material, E the internal energy {J} and C the thermal capacity {J/K}. Because any number of connections can be made, successive ports are named p1, p2, p3 etc. 20-sim will automatically create equations such that the resulting heat flow p.dQ is equal to the sum of the heatflows of all connected ports p1 .. pn. The temperatures of all connected ports are equal to element temperature p.T.

p.dQ = sum(p1.dQ, p2.dQ, ....)

p.T = p1.T = p2.T = ....

The thermal capacity can be calculated with the specific heat capacity cp and material mass m:

C = cp*m;

Typical values for cp are:

 water granite glass aluminium concrete copper silver iron / steel wood air (50 °C) 4186 790 840 900 840? 387 235 452 1674 1046

## Interface

Ports

Description

p[any]

Any number of connections can be made (pseudothermal).

## Causality

preferred temperature out

An torque out causality results in a derivative constitutive equation.

## Variables

E

internal energy [J]

## Parameters

C

T0

thermal capacity [J/K]

initial temperature [K]