Room systems and settings
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Room systems and settings
Internal gains
Internal gains are equipment, occupants and lights in the building. To open the dialog for internal gains, double click in the grey window, see Figure 18.
Figure 18.
Equipment Specific equipment can be chosen by clicking the right arrow and downloading them from the database. The dry convective heating power from appliances in the room is expressed in [W/m2]. Click the hyperlink to open the dialog for setting other equipment details.
Occupants The number of occupants that load the room (dry and wet) is expressed as the number of occupants/m2. Click the hyperlink to open the dialog for setting other occupant details.
Lights The rated input power when lights are expressed in [W/m2]. Click the hyperlink to open the dialog for setting other light details.
Schedules Schedules determine when equipment, occupants and lights are present and active. Click the hyperlink to open the schedule dialog. Specify appropriate hours by drawing a line with the cursor, see Figure 19.
Figure 19.
Indoor climate standard
Double click to open the indoor climate standard object, Figure 20.
In the dialog you can set basic indoor climate settings
Figure 20.
Heating setpoint The air temperature that heating units attempt to maintain [°C].
Cooling setpoint The air temperature that cooling units attempt to maintain [°C].
Method Type of air quality measure [CO2 limit].
CO2 limit - maintain CO2 below the limit.
Limit The air quality setpoint.
Heating
The default heating object is a generic heater. To change the heating object, drag a heating object from the palette to the room tab. Double click to open the heating object, Figure 21. Click the wastebasket to remove the object.
Generic heater
Figure 21.
Double click to open the heating object. The generic heater has by default unlimited capacity. It heats the room directly, using the given energy source, i.e. it does not rely on any central systems that have been defined on the Building tab. The generic heater is normally used in the initial stages, to find required system capacity. 40% of the heat is emitted as long wave radiation.
This ratio can be changed in full ESBO under Advanced settings in the Building tab.
Water based radiator or convector
Figure 22.
Device type To change the type of radiator or convector, right click on the arrow to the right and choose “ Load from database”. Click the hyperlink to access radiator parameters that are stored in the database.
Size The size of the radiator/convector based on [power, front area].
power The emitted power at rating conditions. [W/m2].
Copy Copy data from a previous room unit heating calculation. Design power is shown in the (grey) input field. Corresponding area is shown in the (grey) front area field.
front area The front area of radiator/convector [m2].
Click Rating conditions to see the room and water temperatures at which the given radiator power will be emitted. Note that actual radiator capacity is strongly dependent on these.
Figure 23.
Air to air, non-ducted, heat pump
Figure 24.
Figure 25.
Model for an air-to-air direct expansion on-off controlled unit for heating of room air. At the given rating conditions (press button to see), the model will yield given total power and COP, if it is physically possible. If a physically unrealistic COP is given, the model may yield the required performance at the actual rated point, but may render completely erroneous results at other operating points and may also become numerically unstable.
It is generally not recommended for most users to change any other parameter than the total heating power.
Away from the rated point, the performance will be determined by the additionally specified parameters. With the exception of compressor parameters, the input data are measurable quantities but may not always be made available by equipment manufacturers. If parameters have been optimized with respect to measured data from a real device, the model will predict the performance over the whole operating range within the accuracy of a few percent, typically around one.
Floor heating and/or floor cooling
Figure 26.
The floor heating circuit is assumed to cover the whole floor of a room. Net design mass flow into the circuit from the hot tank is given in terms of a design power and temperature difference. Note that all of this power may not be accessible to the room, if for example the pipes have been located in the middle of an insulation layer.
If the water temperature from the hot tank (that is specified in the Building tab, Heat Distribution system) is unsuitably high for direct injection into a floor coil circuit, the Temperature control option should be chosen (default).
The coil location in the slab may be critical to the resulting heat emission. Overall heat transfer from the pipes to the surrounding material is governed by the H-water-pipe-fin parameter. Some approximate values are given in the form.
Floor cooling is completely analogous, except in cooling mode, the device if fed from the cooling circuit.
Electrical floor heating
Figure 27.
A controllable electrical heat source will be added at a given depth under the floor surface.
Heated beam
Figure 28.
The given power is extracted from the water when temperatures are according to the rating conditions and air flow is at the given design air flow. Some power must also be emitted at zero air flow, otherwise the model may become unstable. If the design air flow is lower than the total supply air flow to the room, the surplus air is injected into the room without passing the beam. Click to open heated beam rating conditions.
Figure 29.
Ventilation
To change ventilation object, drag a new object from the palette to the room tab. Double click to open the ventilation object, Figure 30. Click the wastebasket to remove the object.
Generic ventilation
Figure 30.
Choose Type of ventilation system [Constant Air Volume, Variable Air Volume].
supply The mechanical supply airflow for CAV systems [l/s m2].
return The mechanical return airflow for CAV systems [l/s m2].
min The minimum airflow at VAV [l/s m2].
max The maximum airflow at VAV [l/s m2].
control Control of VAV system [ CO2, Temperature, Temperature + CO2].
| CO2 | The airflow is varied in proportion to the CO2 content of the room air. Minimum requested air flow is kept, when the CO2 level is at or below 500 ppm (vol). (Can be changed under Advanced settings in full ESBO.) Maximum flow corresponds to the PPM level given in the Indoor climate standard object, by default 1000 ppm (vol). |
| Temperature (cooling only) * | Forcing of the VAV flow begins 1°C below the cooling setpoint and full flow is reached at 1°C above the cooling setpoint. VAV is not used for heating for this option. The throttling range, by default 2°C, can be selected under Advanced settings for full ESBO. |
| Temperature + CO2* | Both the temperature setpoint (both heating and cooling) and the CO2 setpoint as given in the Indoor climate standard object are kept using PI controllers, i.e. there is no ‘throttling range’. |
*Note: When any of the temperature controlled VAV schemes are active, the cooling setpoint of any water based unit is displaced by 0.1 °C so that air is used before water to reach the given setpoint.
Cooling
The default cooling object is a generic cooler. To change cooling object, drag a cooling object from the palette to the room tab. Double click to open the cooling object. Click the wastebasket to remove the object. Removing this object will avoid local room unit cooling, but the room may still be supplied with mechanically cooled air. To remove all cooling, remove also the Cooling object from the Building tab (but not the Cold storage).
Generic cooler
Figure 31.
The generic cooler has by default unlimited capacity. It cools the room by convection, using the given energy source, i.e. it does not rely on any central systems that have been defined. The generic cooler is normally used in the initial stages, to find required system capacity. By default, the cooling coil is assumed to hold 15⁰C and may remove moisture from the air.
This temperature can be changed under Advanced settings.
Water based cooling device
Figure 32.
Device type To change the type of water based cooling device, right click on the arrow to the right and choose “Load from database]. Click the hyperlink to edit basic device parameters.
Size The size of the cooling device based on [power, front area].
power The emitted power [W/m2].
Copy Copy data from a previous room unit cooling calculation. Design power is shown in the (grey) input field. Corresponding area is shown in the (grey) front area field.
front area The front area of the cooling device [m2].
Click Rating conditions to see temperature conditions at which the device will remove the specified amount of heat.
Figure 33.
Air conditioner, air to air
Figure 34.
Figure 35.
Model for an air-to-air direct expansion on-off controlled unit for cooling and dehumidifying room air. At the given rating condition (press button to see), the model will yield given total power and EER (cooling COP), if it is physically possible. If a physically unrealistic COP is given, the model may yield the required performance at the actual rated point, but may render completely erroneous results at other operating points.
It is generally not recommended for most users to change any other parameter than the total cooling power.
Away from the rated point, the performance will be determined by the additionally specified parameters. With the exception of compressor parameters, the input data are measurable quantities but may not always be made available by equipment manufacturers. If parameters have been identified with respect to measured data from a real device, the model will predict the performance over the whole operating range within the accuracy of a few percent, typically around one. Click to open the rating conditions, by default according to EN14511.
Figure 36.
Chilled beam
Figure 37.
Given power is absorbed by the water in the beam when temperatures are according to the rating conditions and air flow is at the given design air flow. Some power must also be absorbed at zero air flow, otherwise the model may become unstable. If the design air flow is lower than the total supply air flow to the room, the surplus air is injected into the room without passing the beam. Click to open the rating conditions dialog.
Figure 38.
Combined systems
Combined systems are systems with both heating and cooling.
Fan coil
Figure 39.
A fan coil is used for both heating and cooling. For a real device, a fan is used to circulate room air through the device in order to enhance heat transfer. In the simulation model, the fan only serves as a point of electricity consumption and the fan power may be set to zero. In fact, this is the simplest device to use for heating and cooling the room by water from the plant.
Active beam
An Active beam is a combination of a Heated beam and a Chilled beam.