8.4.3. Radiant heating calculation options<br>

### 8.4.3. Radiant heating calculation options

The next tab displays – after determining the supply temperature and opening the tab or clicking the “Next” button – results of radiant heating calculations, which by now have been performed. This tab is described here, as it is possible on this tab to adjust manually the pipe spacing values for individual heating planes. At this stage already messages on errors in radiant heating calculations may occur and make further calculations of the entire system impossible. A yellow window with error messages appears then, and fields in the result table corresponding to these errors are highlighted in red. You can get more information on selected errors by clicking individual errors in the message window (cursor in the result table marks the appropriate fields) and then pressing the F1 key.

The centre of this tab is occupied by the table of results. At the bottom there is a table with yellow background for messages referring to calculations. Yellow colour also highlights these rows or cells of the table where warnings have occurred.

The structure of the table is as follows:

Manifold label

The line with manifold label (description) starts at the left edge of the calculation options tab. All lines located below, down to the next manifold label or label of HZ’s heated by pipe feeds, display results for rooms and their HZ’s associated with the given manifold. The line describing a manifold consists of the following fields:

- Type of manifold inserted: < Manifold_Symbol > – symbol (name) of the manifold;

- Supplied from: <Symbol_CC> (ts/qs = ...0C) – symbol of supply source of control circuit to which the manifold is assigned and (in brackets) supply temperature determined for that circuit (in effect, the supply temperature of the manifold);

- No. of outlets: <...> – number of outlets in the manifold, including spare outlets, if such were specified in data;

- Settings on: <s.r.> – location of manifold valves on the supply (s) and/or return (r) side;

- G: <... kg/h> – total mass flow in manifold;

- Avail. press. <... Pa> – pressure available at the manifold.

Room label

The line with results for the room is located above the line bordering the results for the first HZ, slightly indented. All lines located below with results for individual HZ’s, down to the next room label or next manifold label, refer to the same room. This line may be of various colours: black colour indicates that the attained floor heating output corresponds to the required value, red colour indicates overheating, blue colour indicates shortage of output. This line consists of the following fields:

- Room: <Symbol_ Room> – symbol (name) of the room;

- ti/qi = <... °C> – temperature inside the room;

- Q/Frh = <... W> – the required output of radiant heating, determined in the room data on the basis of heat loss minus loss to floor and contribution of floor heating to the heating of the room;

- Surplus Q/F = <... W> – the difference between output provided and output required. Positive value indicates excess of output in relation to requirements (line in red colour), negative value indicates shortage of output (line in blue colour). The value in the field takes into account the total output from all HZ’s within the room.

- No. of HZs: <...> – number of heating circuits within the room;

- ts/qs acc. to EN: <...°C> – supply temperature of the circuit of the given room according to EN standard.

Results for heating zone (HZ)

Each HZ in the system has one result bar in the table of results. It contains the most important, with regard to calculations, data and all of the important heat and flow calculation results for the HZ. Immediately below the line with room label there are result bars for the HZ’s associated with the room and connected to the manifold described. If the room also has HZ’s connected to other manifolds or heated by pipe feeds, their result bars will appear in other location of the table.

The contents of the individual fields of the result bar correspond to the headings of the table of results located at the top of the table on grey background. The bar has two lines and many of the fields contain several values in each of them.

- HZ Symbol – top line: symbol (name) of HZ.

- Floor covering / Rlb [(m2K)/W] – bottom line: type of floor covering and its heat resistance. If a numerical value was entered as the covering, rather than being selected from the list of available options, <cov. unknown> appears along with the specified value of heat resistance of the covering.

- Qreq/Freq [W] – the required total output of the HZ, assigned to it during automatic distribution of Q/F or specified by the user.

- Surp. Q/F [W] – the difference between output provided and output required. Positive value (red) indicates excess of output in relation to requirements; negative value (blue) indicates shortage of output. The sum of surplus outputs of HZ’s within the room is equal to the value in the “Surplus Q/F” field in the room label.

- Dt/Dq [K] – calculated temperature drop of the heating medium in the circuit. This always applies to the entire circuit. also in the case of an integrated peripheral zone (cPZ or uPZ).

The button on the right side of this field with an arrow pointing down opens a window for selecting automatic determination or manual specification of Dt/Dq. The appearance of the window is as follows:

- PZ / OZ – this field describes the contents of the following three fields with which it creates a set of results separated from other fields by continuous vertical lines.

If the HZ has no integrated peripheral zone, “OZ” appears in the top line in case of circuit that forms occupied zone or “PZ” in case of circuit defined as peripheral zone forming a separate circuit. Bottom line remains empty.

In the case of HZ with PZ integrated with OZ, the top line displays “cPZ” for a PZ created by compacting the pipe laying pattern or “uPZ” for a PZ connected upstream of OZ. In the following three result fields, the first line refers then to this integrated PZ. The bottom line displays “OZ” and the second line of the following three result fields will then refer to the part of circuit that forms occupied zone.

- area [m2] – effective area of HZ or of separate parts of HZ (see explanation of “PZ / OZ" field). Covers the total effective area of HZ, including the area of pipe feeds running across the HZ. In case of HZ’s with integrated PZ, the area of pipe feeds is always subtracted from the part of HZ forming OZ, even if the pipe feeds on the drawing run across the peripheral zone.

- T (or other designation, depending on the manufacturer: B, b, p, r, VA; units: [cm] or [m] or [mm]) – pipe spacing within HZ or in its separate parts (see explanation of “PZ / OZ” field).

The button on the right side of this field with an arrow pointing down enables expanding a list of available pipe laying spacing distances for the HZ and selecting spacing other than default. The appearance of the list is as follows:

The list includes a “Spacing ...” field, result fields for this option – “Surplus Q” and “td [K]”. If “Auto” is selected, the optimum option with regard to heating conditions is selected. If other option is selected, it will be labelled as “Manual”. The manually selected option is stored and will not be changed when doing subsequent calculations. To revert to optimum option select “Auto”. After selecting other pipe laying spacing option, it will be placed on the results bar of the HZ and the remaining result fields will be altered accordingly.

If a pipe spacing distance causes excessive increase of tfs/qfs_max, even when using maximum temperature difference, a “Standard exceeded” message appears and this spacing becomes unavailable. If the return temperature is too low in relation to ti/qi, even at the lowest possible Dt/Dq, a “ts/qs too low” message appears and again the spacing becomes unavailable. When all options are unavailable, the entire result bar of the HZ is highlighted with yellow colour and appropriate message appears in the error list.

- tfs/qfs/q [0C] / [W/m2] – temperature of floor surface (average) / heat flux density (output obtained from 1 square metre) calculated for the HZ or its part (see explanation of “PZ / OZ" field).

- Area feeds pass. – surface area of pipe feeds running across. Displays the calculated total surface area of pipe feeds running across the HZ. The area depends on the lengths of individual fragments of pipe feeds and their spacing of pipe laying determined by the program or specified by the user.

- Qfeeds/Ffeeds [W] – output of pipe feeds running across. Depends on the total area of pipe feeds, spacing of pipe laying used for individual fragments of pipe feeds, insulation of pipe feeds, percentage of utilisation of their output and system operation conditions.

- Total len. pipes – top line: total length of pipes of the heating circuit, including the length of pipe feeds

- feed+circ. – bottom line: length of pipe feeds running from manifold to the circuit + length of pipe forming the proper heating circuit. The sum of these two values is equal to the total length in the top line.

- Flow [kg/h] – top line: mass rate of flow of heating medium in the circuit

- [m/s] – bottom line: velocity of flow of heating medium in the circuit.

- Press.drop pipe + fit. – top line: linear pressure drop in circuit including pressure drop on pipe fittings connecting the manifold

- s.v.; r.v. [kPa] – bottom line: pressure drop on valves installed on manifold. The first figure represents pressure drop on valve on the supply end, the second figure is for pressure drop on valve on the return end.

If the manifold is not adjusted, some of the fields may not be filled in. In the case of an adjusted manifold, this field will be displayed in bold font for the HZ that determines the required available pressure.

! Note: in order to calculate the total pressure drop after adjustment, the three values displayed in this field should be added together. The total should be approximately equal for all HZ’s connected to the manifold and should correspond to the pressure available on the manifold. If significant deviations of this total occur for some HZ’s, resulting from the valve adjustment range being exceeded, this will be indicated accordingly in the error list.

- Valve set. – setting of valve on the manifold. Letter in brackets indicates whether the setting refers to the valve on the supply end – “(S)”, or on the return end – “(R)”. This field is filled in only when the entire manifold is adjusted.

The structure described above does not include zones heated by pipe feeds. As these HZ’s cannot be assigned to any manifold (HZ may be crossed by pipe feeds running from different manifolds), results for HZ’s heated by pipe feeds are displayed separately and are grouped within a section following the last manifold of that sheet.

The relative arrangement of label of the group of HZ’s heated by pipe feeds, room labels and result bars for individual HZ’s is identical to that of standard HZ’s. The only difference is in the range of fields and their meaning.

Label of a group of HZ’s heated by pipe feeds

The status of the results header for this type of HZ is similar to that of the manifold label, it therefore borders with the left edge of the results tab. Room labels and result bars for HZ’s heated by pipe feeds of the sheet are displayed below. The header consists of the following fields:

Zones heated by pipe feeds assigned to source: <Source_Name> – name of the source supplying the control circuit.

Room bar

Results bar of HZ heated by pipe feeds

This bar has the same fields as that of a standard HZ. However, not all of them are filled in. Important fields include:

- HZ Symbol – same as for standard HZ.

- Floor covering / Rlb [(m2K)/W] – same as for standard HZ.

- Qreq/Freq [W] – same as for standard HZ.

- Surp. Q/F [W] – same as for standard HZ.

- area [m2] – same as for standard HZ.

- T (or other designation, depending on the manufacturer: B, b, p, r, VA; units: [cm] or [m] or [mm]) – pipe laying spacing valid for those pipe feeds running across the HZ heated by pipe feeds, for which the (auto) option was selected in properties. Some pipe feeds may be laid with other spacing specified by the user in properties. Detailed information is given in the table of results for individual pipe feeds displayed when printing.

- Area feeds pass. – same as for standard HZ.

- Qfeeds/Ffeeds [W] – output of pipe feeds running across. It is also the total output obtained from HZ’s of this type.