Nawaf Al-Mutawa

Investigating the Applicability of Different Thermal Comfort Models in Kuwait Classrooms Operated in Hybrid Air-Conditioning Mode

A field study to investigate the applicability of different thermal comfort indices was conducted in Kuwait classrooms operated in a hybrid air-conditioned mode, to assess thermal conditions during the school day. In Kuwait, the girls’ and boys’ schools are completely separated at all academic levels thus offering a wide range for investigating differences in thermal comfort sensations between both genders. A modified questionnaire was used to collect responses from lower age groups of pupils while thermal comfort variables were measured at the same time. However, this paper reports on findings for pupils in the age range 11-17 years. Data analyzed suggested that the different thermal comfort indices (PMV, ePMV, PMV10 and adaptive model and various comfort equations) under-predicted the students’ actual thermal comfort sensation on the warm side of neutral and over-predicted thermal sensation on the cool side of neutral on the ASHRAE comfort scale for both genders. Higher neutral temperatures were also predicted than those resulting from the students’ actual mean vote (AMV). A difference in neutral temperature was found between both genders.

Exergetic and sustainability analysis of an intercooled gas turbine cogeneration plant with reverse osmosis desalination system

AbstractIn this study, an advanced cogeneration plant based on a 100-MW aeroderivative intercooled gas turbine (ICGT) engine and large two-pass reverse osmosis (RO) desalination system is analyzed ...

Evaluation of Human Thermal Comfort in Offices in Kuwait and Assessment of the Applicability of the Standard PMV Model

It has been known that the human thermal comfort is not exclusively a function of air temperature but also a function of six additional parameters, namely, mean radiant temperature, air velocity, turbulence intensity, humidity, activity level, and clothing insulation. The combined physical and psychological impact of these parameters on thermal comfort is mathematically described in various comfort models. The current comfort models, while use extensive human comfort data, may not be applicable in all world regions due to environmental conditions and people’s expectations. The State of Kuwait has a population of 2.5 million inhabitants with majority of people living in a few populated cities with heavy vehicle traffic, office buildings, factories, petroleum operations, and shopping centers. During the summer months (especially in July and August) the temperature reaches 48 °C in the afternoon, and can sometimes exceed 55 °C requiring extensive use of air conditioning. The traditional clothing (Disdasha) is made of lightweight, white, fabric material to provide some level of comfort. To better understand the regional preferences and assess the applicability of the standard comfort models in Kuwait, important parameters influencing human thermal comfort were measured in ten different government offices and the corresponding PMV indices were calculated. The results were compared with other comfort indices to obtain the most viable comfort index and the appropriate temperature range for local comfort for Kuwait offices. This study is not only important for comfort evaluations but also for evaluation of energy consumption in office buildings.© 2004 ASME

Exergetic and Environmental Analysis of 100 MW Intercooled Gas Turbine Engine

This chapter presents energy, exergy, and environmental analysis of 100 MW intercooled gas turbine engine inspired from LMS 100 GE, a state-of-the-art aeroderivative gas turbine engine, which offers the highest simple-cycle thermal efficiency today. The proposed models have been modeled using a software package called IPSEpro and validated with manufacturer’s published data. In fact, most gas turbine engines are designed using energetic performance criteria based on the first law of thermodynamics. Exergetic performance criteria is based on the first and second laws of thermodynamics (Yilmazoglu and Amirabedin, 2011), which when combined are considered more efficient in energy-resource use owing to the way in which locations, magnitudes, and types of wastes and losses in the system are determined. The performance of gas turbine engine was investigated using different loads and ambient temperatures on two configurations. The first include intercooling gas turbine (ICGT) system (Case I), whereas the second is simple-cycle gas turbine (SCGT) engine (Case II). Results show that intercooler system improves gas turbine performance, whereas they have negative impact on combustion chamber due to reduction in inlet temperatures. Load reduction causes an adverse effect on performance, whereas ambient temperature reduction causes the reverse. From an environmental perspective, the present study has developed a new exergetic–environmental indicator to relate the efficiency with nature of exhaust gases in order to measure environmental impacts and increase the lifespan of energy resources. All environmental indicators show ICGT as more appropriate to environment in comparison to SCGT. Furthermore, it achieved the lowest level of CO2 emissions per KWh.

Exergetic, exergoeconomic and exergoenvironmental analysis of intercooled gas turbine engine

Exergetic and exergoeconomic and exergoenvironmental analyses have been performed for an advanced aero-derivative intercooled gas turbine engine. The proposed system was modelled using the IPSEpro software package and validated using manufacturer’s published data. The exergoeconomic model evaluates the cost-effectiveness of the gas turbine engine based on the Specific Exergy Costing [SPECO] method. The CO2 emissions per KWh were estimated using a generic combustor model, HEPHAESTUS, developed at Cranfield University. It is well known that the exergetic analysis can determine the magnitudes, locations and types of losses within an energy system. The effect of load and ambient temperature variations on gas turbine performance were investigated for two different configurations. The first system, Case-I, was a simple gas turbine (SCGT) engine, and the second, Case-II, an intercooling gas turbine (ICGT) system. The latter enhances gas turbine efficiency but, at the same time, has an adverse effect on the combustion chamber due to reduced compressed air temperature. It was confirmed that full load and low ambient temperature are preferable due to the low waste exergy. The unit exergy cost rate for both SCGT and ICGT have been calculated as 8.59 and 8.32 US

Impact of ventilation modes on carbon dioxide concentration levels in Kuwait classrooms

/GJ respectively. The exergoenvironmental results show the ICGT achieved lower emission levels and is more environmentally friendly than the SCGT.