#
Improving Energy Savings of a Library Building through Mixed Mode Hybrid Ventilation^{ †}

^{*}

^{†}

## Abstract

**:**

## 1. Introduction

## 2. Methodology

^{2}with 5 inch concrete radiant slab. To condition the space, radiant slab for both heating and cooling is used in south, east and west perimeter zone of the building and an underfloor air distribution (UFAD) system is applied for the rest of the area. South façades are double glazed, low-e, argon-filled windows to increase passive solar gain and all other façades are triple glazed, low-e, argon-filled to minimize thermal losses. Window-to-wall ratios (WWR) in south, north, east, and west sides are 30, 10, 20, and 30 percent, respectively.

#### Thermal Network

_{aux}, is calculated at each time step by applying proportional control as in Equation (5). The daily cooling load is the integration of Q

_{aux}at each time step over 24 h interval.

- A
_{i}: area of surface i (m^{2}); - h
_{c,i}: convective heat transfer coefficient of surface i (Wm^{−2}K^{−1}); - σ: Stefan-Boltzmann constant (Wm
^{−2}K^{−4}); - F
_{i,j}*: radiative exchange factor between surfaces i and j; - T
_{m}: mean surface temperature (°C); - U
_{i,j}: thermal conductance between nodes i and j (WK^{−1}) - Q
_{i}: heat at node i (due to internal heat gain, solar heat gain or auxiliary heat) (W) - k
_{p}: proportional control - T
_{sp}: set-point temperature (°C) - T
_{i}: temperature at node i (°C) - C
_{i}: thermal capacitance of node i (JK^{−1}) - Δt: simulation time step (s)

## 3. Model Verification

## 4. Simulation Strategies

## 5. Results and Discussion

## 6. Conclusions

## Author Contributions

## Acknowledgments

## Conflicts of Interest

## References

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No. | Description |
---|---|

Node #1 | Room Air |

Node #2 | Interior surface of the radiant floor |

Nodes #3 & #4 | Inside radiant floor (discretized into two control volumes, C_{3} and C_{4}) |

Node #5 | Inside walls and roof (considered as one control volume, C_{5}) |

Node #6 | Node at the interior surface of walls and roof (considered as one node) |

U12, U16 | Convective conductance between air node and interior surfaces |

U26 | Radiative conductance between interior surfaces |

U23, U34, U56 | Conductive conductance of surfaces due to thermal mass |

Uinf | Conductance due to infiltration through windows |

T0, Tb | Ambient and basement temperature |

Tsp_air, Tsp_floor | Set-point temperature of room air and radiant floor |

S2, S6 | 70% and 30% of total solar gain absorbed by the floor and the remaining surfaces |

AirQ_{aux}, FlrQaux | Auxiliary heating/cooling source for room air and radiant floor |

Cooling Mode | Set-Point Temperature T_{sp} | Motorized Window (Open/Closed) | |
---|---|---|---|

Baseline (no shading) | 100% mechanical cooling | T_{sp_air} = 24 °CT _{sp_floor} = 23 °C | CLOSED |

Baseline (shading 11.00 a.m.–4.00 p.m.) | 100% mechanical cooling | T_{sp_air} = 24 °CT _{sp_floor} = 23 °C | CLOSED |

HV with fixed schedules (4 ach) | Mixedmode cooling | T_{sp_air} = 24 °CT _{sp_floor} = 23 °C | CLOSED (9.00 a.m. to 6.00 p.m.); Otherwise OPEN |

HV with fixed schedules (6 ach) | Mixedmode cooling | T_{sp_air} = 24 °CT _{sp_floor} = 23 °C | CLOSE (9.00 a.m. to 6.00 p.m.); Otherwise OPEN |

HV with variable schedules (4 ach) | Mixedmode cooling | T_{sp} = 24 °C (8.00 a.m. to 4.00 p.m.) T _{sp} = 26 °C (remaining hr) | OPEN (T_{amb} ≈ 15 °C to 25 °C) |

HV with variable schedules (6 ach) | Mixedmode cooling | T_{sp} = 24 °C (8.00 a.m. to 4.00 p.m.) T _{sp} = 26 °C (remaining hr) | OPEN (T_{amb} ≈ 15 °C to 25 °C) |

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**MDPI and ACS Style**

Sultana, S.; Athientis, A.K.; Zmeureanu, R.G.
Improving Energy Savings of a Library Building through Mixed Mode Hybrid Ventilation. *Proceedings* **2019**, *23*, 3.
https://doi.org/10.3390/proceedings2019023003

**AMA Style**

Sultana S, Athientis AK, Zmeureanu RG.
Improving Energy Savings of a Library Building through Mixed Mode Hybrid Ventilation. *Proceedings*. 2019; 23(1):3.
https://doi.org/10.3390/proceedings2019023003

**Chicago/Turabian Style**

Sultana, Sormin, Andreas K. Athientis, and Radu G. Zmeureanu.
2019. "Improving Energy Savings of a Library Building through Mixed Mode Hybrid Ventilation" *Proceedings* 23, no. 1: 3.
https://doi.org/10.3390/proceedings2019023003