Passive ventilation and cooling systems can offer energy savings when combined into a mechanical ventilation and cooling strategy for office buildings. At early design stages, it is difficult to predict actual energy savings as current design and calculation tools are limited and do not allow assessment for energy reductions when attempting to use typical passive options such as solar chimneys, rain screen facades, ventilated double facades, passive downdraught evaporative cooling and earth ducts. The only passive systems that are directly incumbent to dynamic thermal modelling software are natural ventilation and external solar shading. Currently, impacts of passive systems on annual building energy performance is unclear and lacks clarity. In hot climates, this is even more problematic as buildings need to endure higher external temperatures and solar irradiation. Understanding minimal energy performance reductions for each passive system can aid with design decisions regarding building ventilation and cooling strategies. The aim of this study is to investigate how existing passive ventilation and cooling system design and operational strategies can be improved to reduce mechanical ventilation and cooling energy consumption for commercial buildings in hot climates. Theoretical commercial building models are created using dynamic thermal simulation software to determine minimum mechanical ventilation and cooling energy values, which are verified against published bench marks, known as base case models. These base case models are simulated using weather data from four different hot climates (Egypt, Portugal, Kenya and Abu Dhabi). Impacts of passive system energy performance are afforded by using either dynamic thermal simulation or fundamental steady state analysis identifying approximate passive ventilation and cooling potentials for reducing mechanical energy. These percentage reductions are created based upon passive system parameters and weather data, using appropriate methodology. From these findings new simplified design guidelines, integration strategies and performance design tools are created including a new passive system energy assessment tool (PSEAT) using Microsoft Excel platform to ensure that a wider audience can be achieved in industry. The design guidance and integration strategies are developed and simplified to enable architects, building services engineers and alike, to apply with speed and accuracy influencing the design process and improve confidence in desired passive solution.

The future operation of public low voltage networks has to consider increased decentralised generation using photovoltaic systems for residential application. For utilities it is necessary to determine the maximum permissible installed power of residential photovoltaic systems in sections of the low-voltage network. For this purpose a method based on modelling low-voltage network structures, occurring loads and insolation situations is presented and demonstrated. The maximum permissible installed power of residential photovoltaic systems is fundamentally determined by the structure of the settlement of the affected low-voltage network section. By modifying the generator model the method can be applied too for other types of decentralized generators in the low-voltage network such as fuel cell systems. / Für den Betrieb des öffentlichen Niederspannungsnetzes in Wohnsiedlungsgebieten ist zukünftig mit einem verstärkten Einsatz dezentraler photovoltaischer Energiewandlungsanlagen zu rechnen. Für Netzbetreiber ist es erforderlich, die maximal zulässige Netzanschlussleistung derartiger Anlagen für Niederspannungs-Netzbezirke zu bestimmen. Dazu wird ein Verfahren auf der Grundlage der Modellierung der Struktur von Netzbezirken, der dort auftretenden Belastungen und Einstrahlungssituationen vorgestellt und demonstriert. Die maximal zulässige Netzanschlussleistung dezentraler photovoltaischer Energiewandlungsanlagen wird wesentlich durch die Siedlungsstruktur des betreffenden Niederspannungs-Netzbezirkes bestimmt. Durch Modifikation des Erzeugermodelles kann das Verfahren auch für andere dezentrale Kleinerzeuger im Niederspannungsnetz angewandt werden.

The future operation of public low voltage networks has to consider increased decentralised generation using photovoltaic systems for residential application. For utilities it is necessary to determine the maximum permissible installed power of residential photovoltaic systems in sections of the low-voltage network. For this purpose a method based on modelling low-voltage network structures, occurring loads and insolation situations is presented and demonstrated. The maximum permissible installed power of residential photovoltaic systems is fundamentally determined by the structure of the settlement of the affected low-voltage network section. By modifying the generator model the method can be applied too for other types of decentralized generators in the low-voltage network such as fuel cell systems. / Für den Betrieb des öffentlichen Niederspannungsnetzes in Wohnsiedlungsgebieten ist zukünftig mit einem verstärkten Einsatz dezentraler photovoltaischer Energiewandlungsanlagen zu rechnen. Für Netzbetreiber ist es erforderlich, die maximal zulässige Netzanschlussleistung derartiger Anlagen für Niederspannungs-Netzbezirke zu bestimmen. Dazu wird ein Verfahren auf der Grundlage der Modellierung der Struktur von Netzbezirken, der dort auftretenden Belastungen und Einstrahlungssituationen vorgestellt und demonstriert. Die maximal zulässige Netzanschlussleistung dezentraler photovoltaischer Energiewandlungsanlagen wird wesentlich durch die Siedlungsstruktur des betreffenden Niederspannungs-Netzbezirkes bestimmt. Durch Modifikation des Erzeugermodelles kann das Verfahren auch für andere dezentrale Kleinerzeuger im Niederspannungsnetz angewandt werden.