RadiantLoop
COMING SOON: NEW DOCUMENTATION
Radiant loops are combined heating and cooling surfaces mainly in floor or ceiling which can either provide heating or cooling power to a room or the complete building. The main model task is to calculate the supplied heating an cooling power dependent on current flow temperature, return temperature and hydronic volume flow. Furthermore, an additional model output is the corresponding return temperature of the hydronic system dependent on the parameterized heating/cooling transmission values and internal thermal inertia.
Concretely, the current heating or cooling power is calculated using the systems current medium temperature (TM), current room temperature (TR), partial heat transmission coefficients (i.e κ; floor, ceiling or panel) and corresponding heat transfer coefficient (α).
The partial heat transmission coefficient (κ) represents nominal heating or cooling power of a modeled hydronic heat transfer system including the thermal inertia of the surrounding surface (i.e. floor, ceiling, panel). It is internally calculated in the model by considering nominal heating or cooling power (according availability - 'defineCool') and nominal temperatures (e.g. nominal flow temperature of floor heating system is about 35 °C, nominal room temperature is about 21 °C).
The corresponding heat transfer coefficient (α) represents heat transfer between the heated surface and the room itself. For heated ceilings and cooled floors it is constant at a value of 6.7 W/(m2K). For heated floors and cooled ceilings, on the the other hand, the following basic characteristic of floor heating systems is used to calculate this value:
Here, nominal temperatures for cooling or heating are inserted in this equation to calculate the corresponding temperature difference which in turn is dependent on the nominal heating or cooling power output.
The radiant loop model is parameterized using the size of the affected area (i.e. heated zone surface area) and the nominal heating or cooling power. The heating and cooling power of individual systems are often co-dependent as per system design and characteristics. The individual powers of each system are not always available or calculable. Due to this the following equation is used for calculation:
