6.2. Basic radiant heating units in the system<br>

## 6.2. Basic radiant heating units in the system

### 6.2.1. Heating floor

The concept of heating zone (HZ in short) as used in this application means a single circuit (in other words a loop) of radiant heating – part of heated floor or wall covered by one loop of pipe which starts and ends at a manifold. Therefore, if – for example – maximum length of pipe is exceeded and the circuit has to be divided into smaller circuits, the application divides HZ into, for instance, two smaller HZ’s.

! Heating zone is not equivalent to a single zone of jointless floating floor slab with heating pipes immersed in it, separated from the walls and other slabs by joints. One slab may include several circuits, and consequently it may consist of several HZ’s. If, in construction terms, a given circuit is to form a separate floor slab, it should be singled out using joints. Division without joints enables defining several circuits within one floor slab.

The “Heating floor” component is inserted into “Plan view” type sheets only and is placed within room area. By default the HZ is inserted over the entire area of the room. When you right click the HZ label a pop up menu appears where you can select “Change type to freely modifiable”. “Handles” appear on the edges of the floor which enable changing the size and shape of floor in the room. This operation should only be performed in special cases.

A coloured triangle in the lower corner of each heating zone indicates the thickness of floor built up (structure). By default the “Floor built up thickness designation” drawing option is checked. In the corner of every HZ a triangle appears, the colour of which depends on the floor built up determined automatically or specified by the user.

Additionally a legend may be placed in the drawing to explain the designations (see section 6.6.)

Button on the “Radiant” toolbar:

Appearance on screen (plan view):

“Heating floor” component data:

Heating zone symbol

Text field. Symbol of a heating zone is of descriptive nature and is designed to identify it during editing and in the table of results. By default a symbol identical with that of the room is adopted. When there are several HZ’s in one room, successive letters of the alphabet are added to the name (e.g. Room_a, Room_b, etc.). Any other symbol can be entered here.

In room

Selection field. Symbol of the room with the HZ. HZ is automatically assigned to room, or you select the symbol from the list of rooms.

HZ type

Selection field. Select type of HZ from list. The default type is standard type. When type is changed, the fields in data table are modified accordingly. There are four types of HZ’s:

- “Standard” – heating zone with one coil, calculated in accordance with general rules. This HZ type is assigned to new heating zones

- “Heated by pipe feeds” – this type enables defining, for instance, a corridor as a HZ without dedicated heating circuit, which will be heated by pipes running across it to other HZ’s. Such a HZ cannot have pipe feeds connected to it, and if it was connected beforehand, then these pipe feeds will be disconnected

- “With return temp. restr.” – is, like the standard type, a zone with one circuit (coil). The difference is that the zone is connected to high-parameter network and therefore it requires the use of a return temperature reducer. Significant temperature drops are allowed for such circuits (the values of permissible temperature drop specified in catalogues or in general data are ignored)

- “Multiple circuit” – is a zone with more than one coil within one HZ. During calculations it is assumed that the circuits are of the same length and that pressure drop is the same in each coil (HZ recommended for use over large areas, such as in factory shop floors, instead of dividing a standard HZ).

ti/qi [°C]

Numerical field. Temperature inside the room taken from room data. This field cannot be edited at the HZ level. In order to change Ti, switch to “Construction” layer and modify ti/qi in room data.

ti/qi below [°C]

Numerical field. Temperature below. Two cases are possible here:

If “ti/qi below” has not been specified in room data, the default value in HZ data is 20 degrees and it can be edited at HZ level. This enables varying of “ti/qi below” in heating zones being part of one room when, for instance, there is a basement under part of the room.

If “ti/qi below” has been specified in room data, this value is adopted and cannot be edited at HZ level. To change this value, switch to “Construction” layer and modify “ti/qi below” in room data or delete it (by entering “-“).

Qhz/Fhz [W]

Numerical field. Part of heat loss in room assigned to given heating zone. (auto) means that this value will be determined automatically by the application when Qrh/Frh is distributed among HZ’s in the room. If in room data the “Qrh/Frh distribution ...” field specifies that heat loss is distributed among HZ’s automatically, the contents of the Q/F field in HZ data is not editable.

Otherwise (when manual distribution of Qrh/Frh is specified in room) this field can be edited in HZ data: you can specify heat output to be delivered by HZ.

Occupied area w/o pipes [m2]

Numerical field. Occupied area not covered by floor heating piping, but covered, for instance, by pieces of furniture installed permanently, by a bathtub, or excluded from heating for other reasons. This area reduces the effective area of HZ.

Occupied area with pipes [m2]

Numerical field. Occupied area covered by RH pipes (e.g. under movable furniture) included as effective area. The percentage of output utilised from such area should additionally be specified.

% output utilization of occupied area

Numerical field. Percentage of output utilised from occupied area with pipes.

Effective area [m2]

Numerical field. Effective surface area of HZ – area of floor covered by heating pipes. Value in brackets indicates area determined from the drawing by subtracting strips not covered by heating system along walls and occupied area without pipes. You can specify other value of effective area. Enter “?” to revert to default setting.

Area for bill mat. [m2]

Numerical field. Surface area for bill of materials. This value (i.e. inclusive of peripheral strips) is taken when drawing up list of materials such as insulation or structural panels. The default value is equal to area of HZ within wall faces. Take notice of this field when effective area is entered manually. This field also enables, when drawing up bill of insulation materials, taking into account the entire surface area of a room where heating pipes (and consequently the HZ) cover only part of it. In such case enter the area of the entire room in place of the value in brackets.

Peripheral zone ...

Compound field. Enables defining peripheral zone within HZ:

Radio buttons in the upper part of the window are used to specify whether there is no PZ, or PZ is part of HZ or the entire HZ forms PERIPHERAL zone. If you select the option that PZ forms part of the main circuit, the middle part of the window is activated, where you can specify the edges of HZ occupied by PZ, the width of PZ and the type of PZ: created by compacting pipe laying pattern (cPZ) or forming first part of circuit (connected upstream of OZ – uPZ). The field at the bottom of the window displays the current area of PZ.

You can edit the field by entering letter shortcut and pressing the Enter key: “E” – entire HZ forms PZ, “N” – no PZ, “C” – part, by compacting, “U” – part, upstream.

Covering

Selection field. This field is used to specify the type and heat resistance of floor covering / lining. The resistance of the floor covering is of high importance for radiant heating calculations. Default value in brackets is taken from general data. To specify the required value, you can enter it directly from the keyboard or select one of the preset values displayed after clicking on the button to the right of the field. The contents of the list depend on the selected manufacturer of floor heating system. Floor covering resistance must be within 0 .. 0.15 [(m2 K)/W].

Floor structure ...

Compound field. Structure of the floor. You can open a window for automatic definition of insulation options or manual specification of insulation layers:

In the upper part of the window is a field specifying the floor covering – you can change it here. Below is a field for specifying maximum permissible working load in kN. Below is a field with the total screed thickness (thickness of concrete layer over pipe + pipe diameter + clearance between pipe and insulation). The default value is the minimum thickness of screed taken from catalogue and depends on the fixing system selected and screed type applied.

Radio buttons in the middle part of the window are used to switch between automatic (default setting) and manual specifying of insulation option. When manual option is selected, you can select one of the available options displayed on the drop down list or specify individual layers in the table. Up to 3 insulation layers may be specified – structural panel and 2 layers of insulation panels. The field in the lower part of the window displays floor heat resistance indicator and floor thickness. You can modify these values to make allowance for unusual cases. The total floor resistance (in (m2 K)/W), taken for calculations is displayed in the lower right corner of the window.

Pipe laying pattern ...

Selection field. Specify heating pipe laying pattern in HZ. The specified pattern will be applied during automatic drawing. This field is partly for information purposes, some of the options, however, have an effect on other fields. If “Single meander” option is selected, you cannot use the peripheral zone created by compacting pipe laying (cPZ) – an error message is displayed after launching calculations.

Pipe feeds ... [m]

Compound field. Displays total length of pipe feeds running across the HZ. You can find a detailed description of the pipe feeds table in section 6.5.3.

Label type

Selection field. Select from list the type of HZ label in drawing. After selecting “Configure”, a component appearance window is opened, where you can create (by copying) and configure the labels of components in the drawing. After specifying a new label, it is then available in a pull down list in the table.

Label on printout

Selection field. Switch on/off the printing of the field with HZ label.

Max DeltaP [kPa]

Numerical field. Maximum pressure drop in HZ. Value in brackets indicates default value taken from general data.

Component status

Selection field. Select from list the current status of component: existing or under design. Affects only bill of material.

Default general data

Selection field. You can specify whether the HZ is to use default (standard) general data. Default setting is “Yes”. When “No” is selected, additional fields are displayed in the table, which enable modification of general data:

You can specify pipe fastening system other than the default system selected in general data, change the type and / or diameter of pipe used, specify pipe laying spacing separately for OZ and PZ and change the restrictions on temperature drop of the medium in the circuit (temperature difference – Dt/Dq), also separately for OZ and PZ.

You can also draw the heating floor within a room using the manual drawing component: “Heating floor (manual)” . In this case the shape of HZ is determined by the user.

¨ There is a function that enables fast arrangement of heating zones. To use this function, select “Insert HZ to each room” from the “Components” menu or click the button on the “Radiant” toolbar.