Freshly harvested berries measuring 2 cm in diameter are chilled from 18°C to 7°C in a chiller at 2°C, with a surface heat transfer coefficient of 25 W/m2 K. They are then loaded in 250 kg batches into containers and held for 12 h in a cold store operating at 2°C prior to further processing. Each container weighs 50 kg. The cold store holds an average of 2.5 t of berries and measures 3 m high by 10 m  10 m. The walls and roof are insulated with 300 mm of polyurethane foam and the floor is constructed from 450 mm of concrete. The ambient air temperature in the factory averages 12°C and the soil temperature 9°C. An operator spends an average of 45 min per day moving the containers within the store and switches on four 100W lights when inside the store. Calculate the time required to cool the berries in the chiller and determine whether a 5-kW refrigeration unit using R-717 as refrigerant would be suitable for the cold store. The outside temperature is 20°C. Design the refrigeration system (operating temperatures and refrigerant flow rate). (Additional data: thermal conductivity of the berries 0.127W/(m.K), thermal conductivity of the insulation 0.026 W/(m.K), thermal conductivity of concrete 0.87W/(m.K), specific heat of the berries 3778 J/(kg.K), specific heat of the container 480 J/(kg.K), the density of the berries 1050 kg/m3, the heat produced by the operator 240 W and the average heat of respiration of the berries 0.275 J/kg/s). Assume any information necessary. Provide source for your assumed information

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter3: Transient Heat Conduction

Section: Chapter Questions

Problem 3.12P

See similar textbooks

Related questions

Question

K .1 Freshly harvested berries measuring 2 cm in diameter are chilled from 18°C to 7°C in a chiller at 2°C, with a surface heat transfer coefficient of 25 W/m2 K. They are then loaded in 250 kg batches into containers and held for 12 h in a cold store operating at 2°C prior to further processing. Each container weighs 50 kg. The cold store holds an average of 2.5 t of berries and measures 3 m high by 10 m  10 m. The walls and roof are insulated with 300 mm of polyurethane foam and the floor is constructed from 450 mm of concrete. The ambient air temperature in the factory averages 12°C and the soil temperature 9°C. An operator spends an average of 45 min per day moving the containers within the store and switches on four 100W lights when inside the store. Calculate the time required to cool the berries in the chiller and determine whether a 5-kW refrigeration unit using R-717 as refrigerant would be suitable for the cold store. The outside temperature is 20°C. Design the refrigeration system (operating temperatures and refrigerant flow rate). (Additional data: thermal conductivity of the berries 0.127W/(m.K), thermal conductivity of the insulation 0.026 W/(m.K), thermal conductivity of concrete 0.87W/(m.K), specific heat of the berries 3778 J/(kg.K), specific heat of the container 480 J/(kg.K), the density of the berries 1050 kg/m3, the heat produced by the operator 240 W and the average heat of respiration of the berries 0.275 J/kg/s). Assume any information necessary. Provide source for your assumed information

Expert Solution

Trending now

This is a popular solution!

Step by step

Solved in 3 steps with 10 images

SEE SOLUTION Check out a sample Q&A here

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.