A heat exchanger is a device used to transfer thermal energy between two or more fluids, at different temperatures in thermal contact. This paper focuses on a shell-and-tubes heat exchanger that involves two fluids (hot water and cold water) in contact with each other while the cold water flows through the tubes and hot water through the shell. Heat exchangers have special and practical applications in the feed water cooler in the process industries, power plants, chemical plants, refineries, process applications as well as refrigeration and air conditioning industry. The design calculations were carried out to determine the specifications of essential parameters for the development of the heat exchanger, data generated from the theoretical formulae were used to fabricate the heat exchanger using some locally available and durable materials, and the performance of the system was evaluated. Some of the parameters evaluated include heat duty, capacity ratio, effectiveness, overall heat transfer coefficient, and fouling factor. The heat exchanger was tested under various flow conditions and the results obtained were as follows; cold water inlet temperatures of (26, 26, 26, 27and 27) ºC increased to (59, 44, 39, 47 and 35) ºC after (10, 7½, 6½  8,  and 6) minutes and the hot water temperatures decreased from (100, 80, 75, 87 and 73) ºC to (73, 59, 55, 62 and 50) ºC, respectively. The design data and test data were compared in terms of the heat duty, capacity ratio, effectiveness, overall heat transfer coefficient, and fouling factor, the deviation is found to be 22.87%, 13.99%, 8.98%, 43.30%, and 43.30% respectively. The results obtained proved that the heat exchanger was effective, reliable and provides a good technical approach to evaluate the thermal performance of the heat exchanger and useful in conducting heat and mass transfer practical in thermodynamics laboratory.

A heat exchanger is a device used to transfer thermal energy between two or more fluids, at different temperatures in thermal contact. This paper focuses on a shell-and-tubes heat exchanger that involves two fluids (hot water and cold water) in contact with each other while the cold water flows through the tubes and hot water through the shell. Heat exchangers have special and practical applications in the feed water cooler in the process industries, power plants, chemical plants, refineries, process applications as well as refrigeration and air conditioning industry. The design calculations were carried out to determine the specifications of essential parameters for the development of the heat exchanger, data generated from the theoretical formulae were used to fabricate the heat exchanger using some locally available and durable materials, and the performance of the system was evaluated. Some of the parameters evaluated include heat duty, capacity ratio, effectiveness, overall heat transfer coefficient, and fouling factor. The heat exchanger was tested under various flow conditions and the results obtained were as follows; cold water inlet temperatures of (26, 26, 26, 27and 27) ºC increased to (59, 44, 39, 47 and 35) ºC after (10, 7½, 6½  8,  and 6) minutes and the hot water temperatures decreased from (100, 80, 75, 87 and 73) ºC to (73, 59, 55, 62 and 50) ºC, respectively. The design data and test data were compared in terms of the heat duty, capacity ratio, effectiveness, overall heat transfer coefficient, and fouling factor, the deviation is found to be 22.87%, 13.99%, 8.98%, 43.30%, and 43.30% respectively. The results obtained proved that the heat exchanger was effective, reliable and provides a good technical approach to evaluate the thermal performance of the heat exchanger and useful in conducting heat and mass transfer practical in thermodynamics laboratory.

Famers do spray seeds, fertilizers, pesticides, herbicides, etc. to protect crops from different insects, pests, diseases and have good harvests. Hand and fuel operated spray pumps are the most common sprayer used in Nigeria. The sprayer causes user fatigue due to excessive bulky and heavy construction, a user can't use it for more than five (5) hours without getting tired, the fuel sprayer is expensive to maintain, emits carbon dioxide and harmful to our environment. In this study, a movable solar operated sprayer for the farming operation was designed and fabricated to overcome these difficulties. The system operates in both direct mode and indirect mode. In the direct mode, the sprayer is operated from the electricity generated by 50W solar panel mounted on a movable frame and in the indirect mode it is operated on stored electrical energy in the lead-acid DC battery (12 V, 12 Ah). Priming diaphragm pump of 10W or mini DC reciprocating cycle motor of 5W is used to generate the required operating pressure to spray the liquid pesticide formulations. The capacity of the storage tank is 20 liters for uninterrupted operation of 25.1 minutes with the discharge rate of 0.79 L/min through the electric flexible mists high-pressure multiple sprayers with four (4) nozzles. Data generated from the theoretical formulae were used to fabricate the system using locally available and durable materials. The sprayer was tested in farmland on two different crops after charging the battery for 3 hours in sunlight. The results obtained were as follows: Power conversion efficiency 20.4%, the time required to charge the battery 2.88hrs, time taken to spray 1 acre of land 2.13hrs, backup time of spray 14.5hrs, application rate    and operating time of the battery 8hrs. The results obtained show that solar sprayer was effective and will be useful in rural areas where there is no constant power supply. The system is incorporated with an energy bulb and charging kit to light up the farmyard and for the operator to charge his/her phone.