3.1.2. Components that form project on sheets<br>

### 3.1.2. Components that form project on sheets

Each system must start with a source. You can accommodate in one project several systems originating from several different sources. These systems, however, must be completely separate. Calculations of theses systems will be done in one cycle and each of the sources may have other circulating medium and different thermal and hydraulic parameters.

A terminal unit may be a convector, radiant heater (floor or wall heating coil), heating riser or a unit not being a heater (this is the only permissible type of terminal unit in a cooling medium system).

Flow through components include pipe-runs, pipe feeds of radiant heaters, three- and four-way valves, manifolds, mixers and bypass bottles.

! System pipe-runs and radiant heating pipe feeds are components of different type. Pipe-runs are used to draw the system diagram and to connect manifolds with the source. Pipe feeds are used only to create connections between manifolds and individual heating zones.

Pipe-runs may have fitting components on them: valves (flow-through), pumps, etc. Some fitting components are designed for installing on radiators: integrated radiator valves and couplings. Three- and four-way valves constitute a specific type of fittings, which are not placed on pipe-runs, but form junctions connecting pipe-runs. Such layout is applied in some types of one-pipe heating systems and when connecting terminals of cooling systems.

If radiant heating system is to be supplied with a medium of a lower temperature than at the source, then temperature reducers must be used, which consist of typical mixing units with additional pump, or special manifolds must be used, which provide the possibility of mixing return water with supply water.

Most of the components that make up the system, first of all pipe-runs and valves that perform control functions, prior to calculations must be assigned to products specified in catalogues included in the program. Some component types (user-specified terminal units, bypass bottles, sources, pumps, pressure gauges, thermometers) cannot be assigned to any catalogue products – the basic parameters for calculations are specified in the data or are determined by the program. Radiators do not have to be assigned to catalogues – in this case they are not sized and checked, and pressure drop across these radiators is neglected.

The basic structural component of a building is a partition. A polygon enclosed by partitions forms (on a plan view) a room, and a set of horizontally adjacent rooms on the same sheet forms a plan view of a storey. Such objects can be created in the graphical editor in Instal-therm, or they can be imported from a drawing created using CAD software and saved to a DWG or DXF file. Usually one file with a drawing consists of a plan view of one storey forming an individual sheet. This file, when loaded, is interpreted to enable identification of rooms on the storey. The structure of the storey then forms a base for placing a plan of the system on that storey, and – independently and optionally – a basis for calculating heat losses in Instal-heat&energy. The presence of a sheet (or sheets) with plan views of storeys in the project file is indispensable for designing a floor or wall heating system, as the entering and editing of heating zone data is tied to the so-called graphical room, that is an object that ensues from a complete and consistent plan view of a storey.

As Instal-therm and Instal-heat&energy write data to a common file, the rooms in the graphical editor may come from:

- from Instal-heat&energy, if they were created there – then we have the so-called non-graphical rooms,

- from the interpretation of a plan view, or created by basic components (walls) - graphical rooms,

- from the editor of building structure Instal-therm – non-graphical rooms.

Non-graphical rooms can exist on graphical storeys (this makes the building structure obscure and is not recommended) and on non-graphical storeys (examples: basement or an attic of which there is no plan view). Graphical rooms exist on graphical storeys only.

Detailed description of the features of all the objects mentioned above is given in further sections of this manual.