Journal of Energy Engineering

The paper proposes two measurement techniques for estimating the duct leakage in residential buildings. The first technique determines the “local” leakages using commercially available zone bags and it is called the zone bag-based measurement technique. Zone bags are used to block the flow of air in ducts so that portions of the duct can be isolated and pressurized separately to measure the respective leakages. The thrust of this technique is to locate where these potential leaks are in the duct system and try to provide more cost effective ways to remedy those leaks than what is available currently. The other technique determines the “total” supply and return leakages using a simple model and it is called the model-based measurement technique. The model is based on pressure drop measurements between the return and supply sides. The proposed techniques were evaluated and validated at the air duct leakage laboratory which has two different air duct configurations and a wide range of leakage levels controlled by holes created at several locations of ductwork. Experimental results indicate that the zone bag-based measurement technique estimates the local leakage accurately with a mean absolute difference of 0.26% of total air-handler flow compared to the baseline. It can be inferred that this method gives a better estimate of the total leakage based on the location of the leak than the duct pressurization method that uses the half plenum pressure technique. The results also show that the model-based measurement technique is a good alternative when one cannot use a physical barrier between the return and supply sides. It was found that the total supply or return side leakage was estimated with a mean absolute difference of 0.6% compared to the baseline technique. The future research step is field testing techniques to examine how one can more efficiently sample the duct system by judicially sectioning off the duct at a few points to obtain localized leakage information and obtain enough information to correct leak problems.

In this study, wind energy density in the southern and southwestern region of Turkey was investigated by using the Weibull and Rayleigh probability density functions, and the wind atlas analysis and application program (WAsP). Hourly wind speeds and directions collected by the General Directorate of Electrical Power Resources Survey Administration were used. Before the construction of the wind turbine generator in these locations, several fundamental properties of the site such as wind behavior, availability, continuity, and probability should be carried out in order to provide the necessary information to the potential investors about cost and economical aspects of planning the wind energy project. The dominant wind direction, probability distribution, Weibull parameters, mean wind speed and power potential of all stations were determined by the Weibull and Rayleigh models, and the WAsP program. The results obtained with these models were compared with the measured data. Finally, it is found that these regions have a reasonable wind power potential and they are suitable for planting wind energy turbines. However, Belen is the most promising and convenient site for production of electricity from wind power.

This paper presents a thermoeconomic optimization analysis yielding a simple algebraic formula for estimating the optimum number of panes for windows. The “ $P_1\text{-}{P}_2$ method,” “the degree day method,” and “the equivalent full load hours energy estimation method” are used together with the correlated overall heat transfer coefficient values for single, double, triple, and quadruple pane windows that are used in HVAC and refrigeration applications.