Chapter 7, Problem 7.3DP

Table Q3 is given to collect the temperature of hot and cold water at the inlet and outlet positions in the laboratory using Tube Heat Exchanger (TD360a) by varying the cold-water flow rate to investigate the effect of cold-water flow rate on the heat exchanger’s performance.  (a) Complete all the output parameters indicated in the table given in Appendix 1.  (b) Draw the temperature (TH1, TH2, TC1 and TC2) on the vertical vs position (1, 2) on the horizontal axis for each flow and discuss the effect of cold water flow rate change on the exit temperature of both cold water and hot water.  (c) Draw the graph of Energy Balance Coefficient and Mean Temperature Efficiency on vertical axis and cold-water flow rate on horizontal axis. Discuss the effect of flow rate on the Energy Balance Coefficient and Mean Temperature Efficiency based on your finding.

3. A 6 in x 20 ft uninsulated B.I pipe conveys steam at 385 °F with an average ambient temperature of 85°F. if the cost of the fuel is PhP 250.00 per 106 BTU with the net energy conversion efficiency of 75%, what is the annual cost of the heat lost?  For 6 in. pipe schedule 80:Do = 6.625 inDi = 5.761 in For iron:k = 30 BTU/ hr ft °F for the surface coefficients:hi = 1000BTU/ hr ft2°F ho = 2 BTU/hr ft2 °F

6- The following reading were taken during a test on a surface condenser: Mean condenser temperature = 35°C Hot well temperature = 30°C Condenser vacuum = 69 cm Hg Barometer reading = 76cmHg Condensation rate = 16 kg/min Cooling water temperature inter = 20 °C Cooling water temperature outlet = 32.5 °C Flow rate being = 37500 kg/h Calculate: a- mass of air present per cubic meter of condenser b- quality of steam at condenser inlet c- vacuum efficiency d- condenser efficiency (condenser heat transfer effeteness)

In a large student house supply at a pressure of 2 bar, gauge, and at a temperature 10°C. A wash basin cold tap is located 3 meters above the mains supply, connected to the mains pipe with a copper pipe of internal diameter 15 mm and length 12 meters. When the tap is opened the flow rate of water out of the tap is 24 litres per minute, creating a Fanning friction factor in the pipe of 0.008. cold water is supplied by the mains water a) Calculate the Reynolds number of the water in the pipe and determine if it is laminar or turbulent. b) Calculate the pressure loss from friction, change in elevation, and hence the pressure of the water just before entering the tap. c) Name two assumptions that have been made in order to arrive at your answer to part b) and state if these assumptions under or over predict the pressure of the water just before entering the tap. d) If the value were not given, what procedure would be needed to determine the Fanning friction factor?

Estimate the heat exchanger area needed to cool 55,000 lb/hr of a light oil (specific heat= 0.74 Btu/lb°F) from 190°F to 140°F using cooling water that is available at 50°F. Thecooling water can be allowed to heat to 90°F. An initial estimate of the Overall HeatTransfer Coefficient is 120 Btu/hr.ft².°F.  Show a schematic of the heat exchanger. Estimate the required mass flow rate of cooling water. The LMTD Taking the shell and tube heat exchanger described above how manytubes of 3 inch diameter and 10 ft length should be used?

Hello! I'd like help with the following exercise, from Levenspiel's "Engineering Flow and Heat Exchange". Leftover air at 20ºC and 100kPa is driven by a fan through a horizontal galvanized conduit of 1 m in diameter and 10m in length at a speed of 10 m/s. What size motor should be used if its efficiency is 90% and that of the fan is 20%? I'm not sure where to start. My professor hasn't explained much about this subject.

You would like to use a pipe-based continuous flow hydroponic system. In this configuration, the roots of the strawberry plants are exposed to water that flows continuously through cylindrical pipes, driven by a pressure pump. The pipes are oriented horizontally so that the nutrient-containing water flows in the axial (x) direction. You are wondering whether this design is sufficient to support the needs of your strawberry plants. Your hydroponics system requires you to pay for the costs of the electricity used to heat the water that flows through the pipes. Strawberry plants grow best when their roots are exposed to water at a temperature of 25°C. The water that flows through the pipes is stored in a tank (inside height = 2 m), which sits on the ground outside of a greenhouse. In July, the average air temperature is Tair = 26°C, with heat transfer coefficient hair = 20 W/m2·K. The temperature of the ground underneath the water tank is Tground = 10°C. The heat capacity of water is…

You would like to use a pipe-based continuous flow hydroponic system. In this configuration, the roots of the strawberry plants are exposed to water that flows continuously through cylindrical pipes, driven by a pressure pump. The pipes are oriented horizontally so that the nutrient-containing water flows in the axial (x) direction. You are wondering whether this design is sufficient to support the needs of your strawberry plants. Your hydroponics system requires you to pay for the costs of the electricity used to heat the water that flows through the pipes. Strawberry plants grow best when their roots are exposed to water at a temperature of 25°C. The water that flows through the pipes is stored in a tank (inside height = 2 m), which sits on the ground outside of a greenhouse. In July, the average air temperature is Tair = 26°C, with heat transfer coefficient hair = 20 W/m2.K. The temperature of the ground underneath the water tank is T ground = 10°C. The heat capacity of water is…

1. 400,000 Ibm/hr of 270°F water is to be heated to 370°F by condensing saturated 390°F steam. (The steam does not sub cool upon condensing). Your job is to design the heat exchanger. The following parameters represent constraint your design. number of tube passes 4 tube fluid water being heated number of shell pass shell fluid steam being cooled U (based on outside tube area) 700 BTU/hr – ft² – °F 1 in tube outside diameter tube wall thickness 1/16 in bulk tube fluid velocity 5 ft/s (a) How many tubes are required per pass? (b) How many tubes are required total? (c) Allowing 3 ft for headers and flanges, how long should the exchanger be?