**4. The BIPV-DSF simulation modelling in TRNSYS**

As specified in Section 3, the "Type 56-TRNFlow" component is adopted in the TRNSYS model, which contains the numerical information of the multizone building model including building geometry, load profiles, construction, window glazing properties as well as the airflow input and output values for the proposed BIPV-DSF. The numerical building information is read by the Type 56 or Type 56-TRNFlow from a set of external files having the extensions \*.bui, \*.bld and \*.tm. These files can be generated by running TRNBuild [15]. An available weather data processor Type 15–3 in TRNSYS, which can read data in the IWEC (International Weather for Energy Calculations) format, is used to read the weather data at regular time intervals (for example, one hour for the simulations) from the external IWEC weather file [15]. As shown in **Figure 13**, both the "Irradiation" and "Temperature" (they both are Type 65d) are online graphical plotters that display the selected system variables (that is, solar irradiation and air temperature) while the simulation is progressing, which allows the users to immediately view the output variables; hence, they can know if the simulations run properly [15].

Type 25c is a printer component that prints the variables (for example, zone air temperature, ambient temperature and heating/cooling demand) of the proposed multi-zone building model (for example, the BIPV-DSF) at specified intervals of

**69**

this case.

**Figure 13.**

**Figure 12.**

*The .OUT formatted external file.*

below 120 W/m2

Z-axis [17].

*Numerical Simulation Modelling of Building-Integrated Photovoltaic Double-Skin Facades*

time [15]. In addition, as noted in Section 3, Type 25c is the available component to print simulation results to an output file (an external file), of which the numerical results can be more easily edited by exporting the values from the output file into the Excel spread sheet. It should be noted that daylight or artificial light condition analysis for the multi-zone building cannot be modelled in TRNSYS 17, so the lighting will be only considered as a part of the heat gains for the energy aspect in

The "Weather data" component (Type 15–3) will send the value of outdoor luminous intensity which is directly tied to its calculation of the controllers (AzimuthAngles and Radiation) of solar radiation as shown in **Figure 13** [16]. The "Lights on–off" is an on/off differential controller that generates a control function having a value of 1 or 0 [15]. If the Lights are on, they will stay "on" until the

off, then they will stay "off" until the amount of horizontal solar radiation drops

TRNSYS Simulation Studio is selected to make faster and easier simulation processes for the multi-zone building, in which the "Wizard setting" as a calculation controller is directly created under the Building Wizard and used for adjusting the orientation of the multi-zone building in terms of the pre-defined degrees of the

[16]. For the proposed simulations, the "Building Wizard" type in

; while if the Lights are

amount of horizontal solar radiation exceeds 200 W/m<sup>2</sup>

*Basic model of a multi-zone building in TRNSYS simulation studio.*

*DOI: http://dx.doi.org/10.5772/intechopen.97171*

*Numerical Simulation Modelling of Building-Integrated Photovoltaic Double-Skin Facades DOI: http://dx.doi.org/10.5772/intechopen.97171*


**Figure 12.** *The .OUT formatted external file.*

*Recent Advances in Numerical Simulations*

*The online plotter is implemented by TRNEXE.*

*The online plotter as part of the simulation model.*

**Figure 10.**

**Figure 11.**

**4. The BIPV-DSF simulation modelling in TRNSYS**

As specified in Section 3, the "Type 56-TRNFlow" component is adopted in the TRNSYS model, which contains the numerical information of the multizone building model including building geometry, load profiles, construction, window glazing properties as well as the airflow input and output values for the proposed BIPV-DSF. The numerical building information is read by the Type 56 or Type 56-TRNFlow from a set of external files having the extensions \*.bui, \*.bld and \*.tm. These files can be generated by running TRNBuild [15]. An available weather data processor Type 15–3 in TRNSYS, which can read data in the IWEC (International Weather for Energy Calculations) format, is used to read the weather data at regular time intervals (for example, one hour for the simulations) from the external IWEC weather file [15]. As shown in **Figure 13**, both the "Irradiation" and "Temperature" (they both are Type 65d) are online graphical plotters that display the selected system variables (that is, solar irradiation and air temperature) while the simulation is progressing, which allows the users to immediately view the output variables; hence, they can know if the simulations

Type 25c is a printer component that prints the variables (for example, zone air temperature, ambient temperature and heating/cooling demand) of the proposed multi-zone building model (for example, the BIPV-DSF) at specified intervals of

**68**

run properly [15].

**Figure 13.** *Basic model of a multi-zone building in TRNSYS simulation studio.*

time [15]. In addition, as noted in Section 3, Type 25c is the available component to print simulation results to an output file (an external file), of which the numerical results can be more easily edited by exporting the values from the output file into the Excel spread sheet. It should be noted that daylight or artificial light condition analysis for the multi-zone building cannot be modelled in TRNSYS 17, so the lighting will be only considered as a part of the heat gains for the energy aspect in this case.

The "Weather data" component (Type 15–3) will send the value of outdoor luminous intensity which is directly tied to its calculation of the controllers (AzimuthAngles and Radiation) of solar radiation as shown in **Figure 13** [16]. The "Lights on–off" is an on/off differential controller that generates a control function having a value of 1 or 0 [15]. If the Lights are on, they will stay "on" until the amount of horizontal solar radiation exceeds 200 W/m2 ; while if the Lights are off, then they will stay "off" until the amount of horizontal solar radiation drops below 120 W/m2 [16]. For the proposed simulations, the "Building Wizard" type in TRNSYS Simulation Studio is selected to make faster and easier simulation processes for the multi-zone building, in which the "Wizard setting" as a calculation controller is directly created under the Building Wizard and used for adjusting the orientation of the multi-zone building in terms of the pre-defined degrees of the Z-axis [17].

The thermal and optical properties of the proposed semi-transparent PV panels can be created in WINDOW program (that is, an open access computer program for calculating total window thermal performance indices) [18] if the components of the PV panels are not available in the current TRNSYS database. Electrical productions of the PV panels are calculated separately using Type 567 which is an existing BIPV component in the Thermal Energy System Specialists (TESS) libraries. The TESS libraries (developed by TESS of Madison, Wisconsin) are the new component libraries that contain more than 250 components used in the TRNSYS simulation, in which the components are used for the simulation of PV systems, solar thermal systems, geothermal systems, HVAC systems, and so on. Each of the components has been extensively tested and has the compatible format with TRNSYS Simulation Studio environment [19]. Type 567–5 (**Figure 14**) is used to model a glazed solar collector for the numerical results of electric power and also take the collected thermal energy into consideration, which is the most suitable PV model for the simulation of the electrical performance of the proposed semi-transparent PV glazing in TRNSYS. This model type can be combined with the detailed multi-zone building model (Type 56) that provides the temperature of the back surface of the PV glazing by giving the mean surface temperature [20].

As mentioned earlier, TRNSYS has already been validated and widely used in the BIPV related research activities. Egrican and Akguc [5] calculated cooling and heating demands of an office building with BIPV building façade through TRNSYS simulation, in which the PV panel model (Type 567) was well coupled with the building façade model (Type 56). Kim and Kim [6] evaluated both the electrical and thermal performances of a building with BIPV façade by means of the simulation modelling in TRNSYS, which modelled different cases of the building façade (that is, single-skin and ventilated double-skin façades) using Type 567 as the PV panel model and Type 56 as the building model.

Kamel and Fung [7] developed a roof system model that integrated a BIPV collector with an air source heat pump (ASHP) for a residential house in TRNSYS, in which the Type 567 was selected to model the glazed PV collector and connected to the multi-zone building model (Type 56). The simulation successfully predicted the seasonal performance of the heat pump and the electricity cost savings from the PV production. Elarga et al. [8] created a similar model typology as the proposed BIPV-DSF in this chapter, and investigated the energy performance of a DSF coupled with BIPV system for an office building, but the semi-transparent PV panel

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**Figure 15.**

*Schematic diagram of the BIPV-DSF model in TRNSYS.*

*Numerical Simulation Modelling of Building-Integrated Photovoltaic Double-Skin Facades*

multi-zone building model (that is, Type 56 or Type 56-TRNFlow).

TRNSYS model presented in **Figure 15** are further described in **Table 1**.

**5. Summary of the BIPV-DSF model in TRNSYS**

edited in TRNBuild.

simulation analysis.

was mounted in-between the two skins of the DSF and Type 562 (it modelled the electric power of the PV only) was selected as the model of the PV panel. Also, in this case, the TRNSYS numerical model was validated against the experimental data and used for further analysis for different cases. Generally, the previous simulation studies have well proved the ability and capability of TRNSYS simulation in modelling the buildings adopt double-skin façade coupled with BIPV system, and the Type 567 is considered as the most appropriate component to model the electric and thermal characteristics of the proposed PV window glazing by coupling with the

According to the descriptions in Section 4, the proposed BIPV-DSF model can be created in TRNSYS by employing the determined essential components and types. **Figure 15** shows a complete BIPV-DSF model with all the linked components and types in TRNSYS (Simulation Studio). The system components and types of the

"Type56-TRNFlow" is used to carry out the numerical building information of the BIPV-DSF model, which is able to model the ventilation of the façade/building model in TRNSYS Simulation Studio based on the characteristics of building geometry, while the non-geometry information (for example, building envelope properties, internal heat gains and occupancy) of the façade/building model is

As stated in above, the selected system components and types for the proposed TRNSYS models have already been validated and widely used in the BIPV related research activities, which can be confidently employed to perform the proposed

*DOI: http://dx.doi.org/10.5772/intechopen.97171*

**Figure 14.** *Connection of Type567 and multi-zone building model in TRNSYS.*

*Numerical Simulation Modelling of Building-Integrated Photovoltaic Double-Skin Facades DOI: http://dx.doi.org/10.5772/intechopen.97171*

was mounted in-between the two skins of the DSF and Type 562 (it modelled the electric power of the PV only) was selected as the model of the PV panel. Also, in this case, the TRNSYS numerical model was validated against the experimental data and used for further analysis for different cases. Generally, the previous simulation studies have well proved the ability and capability of TRNSYS simulation in modelling the buildings adopt double-skin façade coupled with BIPV system, and the Type 567 is considered as the most appropriate component to model the electric and thermal characteristics of the proposed PV window glazing by coupling with the multi-zone building model (that is, Type 56 or Type 56-TRNFlow).
