P. Gandhidasan

• King Fahd University of Petroleum and Minerals

The integrated solar absorption heat pump system includes an absorption heat pump assembly (AHPA) having a generator, a condenser in fluid communication with the generator, an evaporator/absorber in fluid communication with the condenser and the generator, and a heat exchanger in communicating relation with the evaporator/absorber; a solar collecto...

This paper focuses on thermodynamic balancing of the regeneration process in a hybrid liquid desiccant cooling/desalination system. The thermal balancing technique is investigated by adding a single extraction between the system regenerator and condenser. This technique is considered as a potential method to reduce energy consumption and increase t...

Air conditioning systems contribute to the largest share of energy consumption in building sector. On the other hand, the systems produce reasonable amount of condensate, especially when operating in humid climates. The aim of this study is to minimize the energy consumption and improve the performance of air conditioning systems utilizing condensa...

The central chilled water system servicing one of the academic buildings at the KFUPM campus located in Dhahran has been modeled numerically to combine with the ejector cooling system. This ejector system cools the water which is in turn utilized to cool the refrigerant in the chiller condenser and hence, the function of the cooling tower in a conv...

The central chilled water system servicing one of the academic buildings in King Fahd University of Petroleum & Minerals (KFUPM) campus located in Dhahran is numerically modeled in detail with a special focus on the pumping scheme. The software Engineering Equation Solver (EES) is used for the modeling and simulation of the system. The bin data alo...

During the last decade, the exploitation of the existing water resources in the Asir region of the Kingdom of Saudi Arabia has considerably increased due to both the decrease in annual precipitation and the added population pressures from the growing tourist industry. To face the conventional water shortage, attention has been mainly focused on des...

The dehumidification process involves simultaneous heat and mass transfer and reliable transfer coefficients are required in order to analyze the system. This has been proved to be difficult and many assumptions are made to simplify the analysis. The present research proposes the use of ANN based model in order to simulate the relationship between...

Ejector-cooling model is developed to calculate the entrainment ratio and the area ratio representing throat to nozzle area. The developed model is validated with available experimental data in the literature. Parametric studies using the refrigerant R134a as the working fluid show that the Coefficient of Performance (COP) of the system is increase...

The heart of the liquid desiccant cooling system is the dehumidification process which is influenced by many parameters. Different types of dehumidification equipment have been developed and a variety of analytical models have been employed to analyze the dehumidification process. The dehumidification process involves simultaneous heat and mass tra...

In order to harvest water present in a humid atmosphere, a suitable absorber/desorber was designed. Experiments were conducted in Dhahran to measure the water absorption rate in the nighttime and the water desorption rate in the daytime. It was found that the water absorption rate was 2.11 L/m2/day and the water desorption rate was 1.15 L/m2/day de...

The region of Asir is located in the southwestern part of the Kingdom of Saudi Arabia between longitudes 41 - 45 E and latitudes 17 - 21 N. Known for its natural beauty and cool climate delight the visitors and the region has become a destination for tourists. One of the main problems in the Asir region is the high demand for water during tourism s...

This paper describes the potential of the development of a seawater desalination system that combines the technologies of reverse osmosis (RO) and photovoltaic (PV) to deliver 100 m3/day of sweet water. Silicon cells are chosen for the PV array and the polyamide thin-film composite seawater Filmtec membranes are selected for the RO system. The soft...

This paper presents preliminary findings of the energy analysis of a cooling system with two-stage evaporative coolers using liquid desiccant dehumidifier between the stages. The proposed evaporative cooling system utilizes air humidity for cooling in humid areas and requires no additional water supply. The major energy requirement associated with...

This article presents the results of an experimental study on the performance of a structured packing dehumidifier and the regenerator system. The system is tested using different proportions of an aqueous desiccant mixture of calcium chloride and lithium chloride solutions with an overall concentration of 40 wt%. The instantaneous effectiveness an...

In this paper a renewable method of obtaining fresh water from the atmospheric air in the form of dew is proposed. This study deals with the dew formation on radiatively cooled pigmented polyethylene foils. Since a large number of variables are involved in the formation of dew, a steady-state mathematical model is formulated using the energy balanc...

This paper presents preliminary findings of the energy analysis of a cooling system with multistage evaporative coolers using liquid desiccant dehumidifier between the stages. The proposed evaporative cooling system utilizes the air humidity for cooling in humid areas and requires no additional water supply. The major energy requirement associated...

This paper describes a relatively simple model for the preliminary design of an air dehumidification process occurring in a packed bed using liquid desiccant through dimensionless vapor pressure and temperature difference ratios. An expression is derived using the aforementioned ratios to predict the water condensation rate from the air to the desi...

In this experimental investigation, a packed bed column suitable for 5-ton hybrid cooling system has been designed to study the absorption of water vapour from moist air by contact with aqueous solutions of calcium chloride. The packing material used in the study was two elements of the BXPEP structured packing and the height of the each element wa...

The current experimental study aims to examine the effects of using oxygenates as a replacement of lead additives in gasoline on performance of a typical SI engine. The tested oxygenates are MTBE, methanol, and ethanol. These oxygenates were blended with a base unleaded fuel in three ratios (10, 15, and 20 vol.%). The engine maximum output and ther...

Natural gas is an important source of primary energy that, under normal production conditions, is saturated with water vapor. Water vapor increases natural gases' corrosivity, especially when acid gases are present. Several methods can be used to dry natural gas and, in this paper, a solid desiccant dehydrator using silica gel is considered due to...

The current paper examines the effects of using MTBE as a replacement of lead additives in gasoline on exhaust emissions of a typical SI engine. The MTBE was blended with a base unleaded fuel in three ratios (10, 15, and 20 vol. percent). The emissions of CO, HC, and NOx were measured at a variety of engine operating conditions using an engine dyna...

Liquid desiccants used for many industrial and domestic applications have to be reconcentrated for reuse. Instead of using thermal energy, a method is proposed in this paper to use mechanical energy for regeneration of weak desiccants. The osmotic pressure required to regenerate two such desiccants, namely calcium chloride and lithium chloride, for...

A computer program referred to as TEG.TRAY enables process engineers and designers to estimate the circulation rate of lean triethylene glycol (TEG) needed to dry natural gas in glycol dehydrators that use a tray column. The program determines the total amount of water vapor to removed from the natural gas to achieve the required exit-gas water con...

The presence of humidity may be detrimental to the operation of pipelines transporting natural gas or other petroleum products. In particular conditions water solidifies or reacts chemically with hydrocarbons, forming hydrates. Such crystalline substances may cause obstruction of the lines and damage the equipment of the relevant facilities. A proc...

We present the applicable exergy analysis and estimate irreversible losses that are generated during operation of a hybrid air-conditioning cycle with emphasis on a partly closed solar regenerator that is used to regenerate weak desiccant. The desiccant mass-flow rate has been chosen as the fundamental parameter for analysing the system. We find an...

Liquid desiccants are widely used in many solar applications. In order to analyze the performance of the system using desiccant technology, the thermophysical properties of desiccants are essential. In particular, the vapor pressure of the liquid desiccant is one of the important properties in air dehumidification. In this paper, an attempt is made...

This paper proposes to use a suitable liquid desiccant to extract fresh water from the humid atmosphere. The night-time moisture absorption and the day-time moisture desorption take place in the same unit. It consists of a flat, blackened, tilted surface and is covered with a single glazing. During the night, the strong absorbent flows down as a th...

A hybrid open-cycle vapor absorption and liquid desiccant system using LiBr for the process of absorption and dehumidification has been simulated. The simulation model of the hybrid cycle is formulated with a partly closed-open solar regenerator for regenerating the weak desiccant and a packed tower dehumidifier for the dehumidification of ambient...

Field-dried peanuts having 25% average moisture content have been dried by using a liquid dasiccant drying system. This system cansirts of climate simulation subsystem, closed loop air drying subsystem, and regeneration subsystem. The closed loop drying subsystem used in this investigation provides low temperature drying with a little increase in d...

To simulate space cooling or drying systems for various geographical regions (low, moderate, and high humidity regions) a liquid desiccant system consisting of a humidifier and dehumidifier has been designed and constructed. This system consists of two coupled humidifying and dehumidifying packed columns filled with plastic Intalox Snowflake packin...

Water precisely fresh water is essential for live. The artificial fresh water production by desalting processes implies the utilization of energy. The ambient atmosphere contains a large quantity of water in the form of vapor and this endless source of water can be recovered for general use. In this paper, a method is proposed to use liquid desicca...

This paper presents a modified open regeneration system suitable for humid climates. The upper part of the open regenerator is covered with a single glazing where the desiccant can be heated up without evaporation of water and the evaporation starts at the beginning of the open surface. For this type of regenerator, performance analysis has been ma...

A tilted solar still has been studied in application to desalinate the seawater. It essentially consists of a flat, blackened, tilted surface with a transparent glazing as a covering. The seawater trickles down as a thin film over the absorber and is heated by solar energy. The water vapor that evaporates from the liquid film is condensed on the un...

An open-cycle solar space-cooling system, which operates on the ventilation mode using a liquid desiccant, has been proposed for places like Dhahran, Saudi Arabia, where the temperature and humidity are high during the summer months. The ambient air is dehumidified ussing a liquid desicant followed by adiabatic evaporative cooling, and the weak des...

In recent years attempts have been made to use packed towers for regenerating weak liquid desiccants in desiccant cooling or drying processes. For regeneration of desiccants, a counter-flow packed regeneration tower in conjunction with a humidifier has been designed and constructed. The tower was packed with plastic Intalox Snowflake packing materi...

Concern over the environment and a potential oil shortage has resulted in an intensified research for alternative fuels for the transportation sector. Two fuels given strong consideration are methanol and compressed natural gas (CNG). This paper is a comprehensive comparative study of methanol and CNG as transportation fuels. The physical propertie...

Dehumidified air is required in many industrial applications. In recent years attempts have been made to use liquid desiccants for dehumidifying air. Dehumidifying with a liquid desiccant usually scrubs the air stream, not only providing conditioning but also cleaning and disinfecting the air. Different liquid desiccants are available in the market...

Roof-spray cooling systems are used to reduce the heat flux entering through the roof of a building by spraying a fine mist of water on the roof surface. This paper presents a simple periodic thermal model to predict the performance of a roof-spray evaporative cooling system. The governing one-dimensional transient equation of heat conduction is so...

Many industrial sectors reject heat to the atmosphere in the form of hot water with a temperature between 40/sup 0/ and 70/sup 0/C. This low grade heat can be upgraded by using a vapor absorption heat transformer (AHT). The present study considers a single stage AHT with binary mixture of NH/sub 3/-H/sub 2/O as the working fluid. The performance ch...

One of the efficient methods of regenerating the weak absorbent solution using solar energy is the forced flow regeneration system. This paper describes a forced flow solar regenerator in which the absorbent solution to be concentrated flows as a thin film over the absorber and the water evaporating from the solution due to absorption of solar ener...