# Development of a Transient Model of a Lightweight, Portable and Flexible Air-Based PV-T Module for UAV Shelter Hangars

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## Abstract

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^{®}software tool to simulate energetic systems. The main advantage of these types of panels is their easy portability, making them ideal to address thermal needs in several scenarios. In the military field, there is an important concern about the use of sustainable energy; for instance, cooling facilities for infantry tents used in their deployments. In this research, a PV-T panel to cover electrical power needs for an infantry’s hangar unmanned air vehicle (UAV) is introduced. The proposed thermal model, based on the novelty of inertial mass (lump) as an approach to real panel behavior, has been validated through the comparison between Trnsys’ model simulation data, a real weather station, and data obtained in a test bed. Genopt’s simulation software is used to fit the model, allowing for the prediction of heat transmission coefficient values. The good match between simulated and experimental data makes the proposed model suitable for the photovoltaic–thermal prediction of panel behavior.

## 1. Introduction

## 2. Materials and Methods

#### 2.1. Experimental Setup

^{3}/h per unit; they operate under PWM, so that flowrate can be controlled, up to a maximum of 8.2 g/s and 4.3 Watts. Figure 3 shows the fans integrated in the test bed:

_{in}) and output (T

_{out}) refrigeration air temperatures, and airflow speed (FR) are logged. Environmental conditions are also logged, inasmuch as they are also relevant; wind speed is obtained using a meteorological station, and the incident radiation on PV-T panel (SI) is measured on workbench.

#### 2.2. Thermal Model

#### 2.3. TRNSYS Simulation

## 3. Results

## 4. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## Nomenclature

$\alpha $ | solar absorptivity [-] |

$\epsilon $ | panel emissivity [-] |

σ | Stefan-Boltzmann’s constant [$\raisebox{1ex}{$\mathrm{W}$}\!\left/ \!\raisebox{-1ex}{${\mathrm{m}}^{2}\xb7{\mathrm{K}}^{4}$}\right.$] |

${A}_{PV}$ | panel area [m^{2}] |

${c}_{p}$ | air flow specific heat [$\mathrm{J}/\mathrm{kg}\xb7\mathrm{K}]$ |

h | convection heat transfer [$\frac{\mathrm{W}}{{\mathrm{m}}^{2}\xb7\mathrm{K}}$] |

G | irradiation [W/m^{2}] $\dot{m}$= mass air flow in cooling duct [kg/s] |

T_{amb} | ambient temperature [K] |

T_{l} | lump mass temperature [K] |

T_{ma} | average temperature of air fluid [K] |

T_{out} | system’s output temperature [°C] |

T_{s} | temperature of surface in touch with air fluid [K] |

T_{sky} | temperature in the surroundings of the system [K] |

V_{w} | wind speed [m/s] ${\dot{q}}_{conv}$= system’s convection losses [W/m^{2}] |

$\dot{Q}$ | heat speed transfer [W] |

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**Figure 9.**PV-T operating scheme: the system is provided with (cold) tent air and solar radiation, supplying heated air and electricity.

**Figure 13.**Experimental actual temperature (T

_{real}) versus simulated (T

_{sim}) during simulation period.

**Figure 15.**Actual output temperature (T

_{real}) versus input temperature (T

_{in}) versus simulated lump mass temperature (°C).

Parameter | Number of Sensors | Sensor | Range | I/O Type | Power Supply |
---|---|---|---|---|---|

Temperature | 2 | DS18B20 Thermometer | −55–125 °C | Digital (One-Wire) | 5 VDC |

Flow rate | 1 | Bosch HFM 5 Air-mass meter | 8–370 kg/h | Analog (0–5 V) | 8–17 VDC |

Solar irradiation | 1 | Kipp & Zonen SMP10 Pyranometer | 0–1600 W/m^{2} | Analog (4–20 mA) | 5–30 VDC |

Simulation Step (h) | ${\mathbf{T}}_{\mathbf{o}\mathbf{u}\mathbf{t}}(\mathbb{C})$ | ${\mathbf{T}}_{\mathbf{i}\mathbf{n}}(\mathbb{C})$ | $\mathbf{\Delta}\mathbf{T}(\mathbb{C})$ |
---|---|---|---|

16 | 17.1 | 10.3 | 6.7 |

34 | 19.9 | 10.8 | 9.2 |

62 | 18.4 | 10.8 | 7.6 |

87 | 21.9 | 13.7 | 8.1 |

111 | 18.9 | 12.7 | 6.3 |

135 | 20.9 | 12.4 | 8.4 |

159 | 21.2 | 12.7 | 8.5 |

183 | 21.7 | 13.7 | 7.0 |

Period | ${\overline{\mathbf{T}}}_{\mathbf{o}\mathbf{u}\mathbf{t}}(\mathbb{C})$ | ${\overline{\mathbf{T}}}_{\mathbf{i}\mathbf{n}}(\mathbb{C})$ | $\mathbf{\Delta}\overline{\mathbf{T}}(\mathbb{C})$ |
---|---|---|---|

Simulation time ($100\%)$ | 7.7 | 6.6 | 1.2 |

Heating time ($37.5\%)$ | 14.9 | 10.0 | 4.8 |

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**MDPI and ACS Style**

Orgeira-Crespo, P.; Ulloa, C.; Núñez, J.M.; Pérez, J.A.
Development of a Transient Model of a Lightweight, Portable and Flexible Air-Based PV-T Module for UAV Shelter Hangars. *Energies* **2020**, *13*, 2889.
https://doi.org/10.3390/en13112889

**AMA Style**

Orgeira-Crespo P, Ulloa C, Núñez JM, Pérez JA.
Development of a Transient Model of a Lightweight, Portable and Flexible Air-Based PV-T Module for UAV Shelter Hangars. *Energies*. 2020; 13(11):2889.
https://doi.org/10.3390/en13112889

**Chicago/Turabian Style**

Orgeira-Crespo, Pedro, Carlos Ulloa, José M. Núñez, and José A. Pérez.
2020. "Development of a Transient Model of a Lightweight, Portable and Flexible Air-Based PV-T Module for UAV Shelter Hangars" *Energies* 13, no. 11: 2889.
https://doi.org/10.3390/en13112889