The Effect of Climate Conditions on the Relation between Energy Efficiency and Urban Form

Urban sustainability has been connected to form and compactness of the urban tissue. At the same time the relationship between urban form and energy efficiency is strongly affected by climate. This paper investigates the effect of climate conditions on the relation between urban morphology and energy efficiency of urban blocks, focusing on the Greek city context. A set of building block typologies is analyzed with regard to their form factors such as S/V ratio, coverage ratio and building ratio for the climatic conditions of two cities, each one belonging to a different climatic zone. Heating and cooling loads are calculated at an urban block scale for the climate of the city of Thessaloniki (zone C) and of the city of Heraklion (zone A) in order to draw conclusions about the relation between geometry factors and energy efficiency. The results of the research indicate that there is a strong relationship between urban morphology factors and energy efficiency and that the total load demand of urban blocks can be described as a function of form parameters. Results of the research, concerning the energy demand calculation, are valuable since they indicate the energy profile of each typology according to climate and can be used for defining different urban strategies towards sustainability in a context-based climate dependent analysis

Hygrothermal performance of log walls in a building of 18th century and prediction of climate change impact on biological deterioration

Several studies underline the dramatic changes that are expected to take place in nature and environment due to climate change. The latter is also expected to affect the built environment. Particular emphasis is currently given to the impact of climate change on historical structures. Within this context, it is important to use simple methods and novel tools in order to investigate pecific case studies. In this study, the climate change impact on the hygrothermal performance of the log walls in a historic timber building is presented. The building under investigation is the Fadum storehouse, also known as ‘the coated house’, located in Tønsberg, Norway. The storehouse dates to the late 18th century. It has a particular design with the main features of stumps or piles up to which it stands and the ‘coating’ that covers its outer walls. The main damage of the construction is related to the biological degradation of the wood. The hygrothermal performance of the log walls, as well as the exterior and interior climate, have been monitored and the results have been used to validate a Heat, Air and Moisture transport (HAM) model. The validated HAM model is then used to examine the performance of the log walls for both current and potential future climate conditions. The transient hygrothermal boundary conditions serve as the input parameters to a biohygrothermal model that is used to investigate the biological deterioration of the building components. The findings reveal that currently there is no mould risk for the main body of the construction, which is in accordance with the visual inspection. The passive systems of the building are highly conducive to these results, since they protect it from driving rain and other sources of moisture and eliminate the potential impact of future climate change risk scenarios

On the Establishment of Climatic Zones in Europe with Regard to the Energy Performance of Buildings

Nowadays, subjects such as eco-design requirements, product rating or code compliance with regard to energy efficiency are expanding towards a pan-European level. This leads to the necessity of defining zones within the European region, which share common climatic characteristics and will further facilitate the quick estimation of building energy performance. Towards this direction stands the current paper; it presents an approach for defining climatic zones in Europe on the basis of the amount of heating and cooling degree days. It is applied for the climate classification of selected European cities and is compared with the conventional scheme based solely on heating degree days. Since the approach is orientated mainly towards the assessment of building energy performance, its outcomes are evaluated with regard to the actual heating and cooling energy needs of a reference building unit with office use located in representative cities of the proposed climatic zones and facing the four cardinal orientations. The classification of climatic zones on the basis of both heating and cooling degree days leads to more realistic results, since nowadays cooling needs form a substantial part of the energy balance of the building, especially in the Mediterranean regions

Energy and thermal modeling of building façade integrated photovoltaics

Electricity generation on site is a design challenge aiming at supporting the concept of energy-autonomous building. Many projects worldwide have promoted the installation of photovoltaic panels on urban buildings, aiming at utilizing a large area to produce electricity. In most cases, photovoltaics are considered strictly as electricity generators, neglecting their effect to the efficiency and to the thermal behaviour of the building envelope. The integrated performance of photovoltaic ventilated façades, where the photovoltaics are regarded as part of a complicated envelope system, provides design challenges and problems that cannot be overlooked within the framework of the Nearly Zero Energy Building concept. In this study, a finite volume model for photovoltaic ventilated façades is developed, experimentally validated and found to have a significant convergence to measured data

Ground source heat pump systems for residential buildings in warm climates: Energy, environmental and economic considerations

In this paper the heating and cooling energy consumption of a typical single-family house is calculated for five selected locations in Cyprus. Hourly calculations are performed using the EnergyPlus software. The results are translated in oil or LPG and electricity consumption, assuming that the typical building in Cyprus is equipped with an oil-fired or LPG-fired boiler for heating and local air-to-air split-type heat pumps for cooling. The same energy needs are assumed to be covered by an alternative system, i.e. a vertical closed loop ground heat exchanger combined with a water-to-water heat pump system for heating and cooling. The ground source heat pump system is dimensioned with the aid of the EED 3.0 software, analyzed using an in-house developed and validated simulation code, and as a result the electricity consumption of the system is calculated. Based on the resulting fuel consumption of the alternative system, the primary energy consumption and the corresponding emissions are determined, while a financial analysis is also performed. The results prove that significant energy, environmental and economic benefits can be achieved