1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
snow_tiger [21]
3 years ago
8

A flat-plate solar collector is used to heat water by having water flow through tubes attached at the back of the thin solar abs

orber plate. The absorber plate has a surface area of 2 m2 with emissivity and absorptivity of 0.9. The surface temperature of the absorber is 35°C, and solar radiation is incident on the absorber at 500 W/m2 with a surrounding temperature of 0°C. Convection heat transfer coefficient at the absorber surface is 5 W/m2 ∙K, while the ambient temperature is 25°C. Net heat rate absorbed by the solar collector heats the water from an inlet temperature (Tin) to an outlet temperature (Tout). If the water flow rate is 5 g/s with a specific heat of 4.2 kJ/kg∙K, determine the temperature rise of the water.
Engineering
1 answer:
-BARSIC- [3]3 years ago
3 0

Answer:

dT = 21.35 C

Explanation:

Given:

- Area of the absorber plate A = 2 m^2

- e= a = 0.9

- T_s = 35 C

- q''_solar = 500 W/m^2

- T_surr = 0 C

- h = 5 W/m^2 K

- T_amb = 25 C

- flow(m) = 5 g/s

- c_p = 4.2 KJ/kgK

Find:

- The temperature rise of water.

Solution:

- Using Energy balance on the plate:

                                   E_in - E_out = q_in

- Find E_in and E_out:

                                   E_in = a*q''_solar

                            E_out = q"_convec + q"_rad

                   E_out = h*(T_s - T_amb) + e*σ*(T_s^4 - T_surr^4)

- Compute E_in and E_out:

                            E_in = 0.9*(500) = 450 W/m^2

         E_out = 5*(35 - 25) + 0.9*5.67*10^-8*(308^4 - 273^4)

                                E_out = 225.778 W/m^2

- Hence,

                                  E_in - E_out = q_in

                                 450 - 225.778 = q_in

                                  q_in = 224 W/m^2

- Assuming thickness of plate and pipe through which water flows as negligible, then:

                                flow(m)*c_p*(dT) = q_in*A

                                dT = q_in*A / flow(m)*c_p

- plug values in:

                                    dT = 224*2 / 5*4.2

                                    dT = 21.35 C

                     

                 

                             

You might be interested in
List one advantage and one disadvantage of the use of the commutator?
Mariulka [41]

Answer and  Explanation:

Commutator are used in DC machine commutator is mainly used for the reversing the direction of the current .It is connected to the armature of the DC generator or motor

ADVANTAGE OF COMMUTATOR The main advantage of the commutator in DC motor is to keep keep the direction of the toque always in the same direction by changing the current direction

DISADVANTAGE OF COMMUTATOR : The main disadvantage is due to the friction between the commutator and brushes there is a friction loss.

3 0
3 years ago
A construction manager is looking for workers to build a series of walkways within a large garden apartment. What type of workme
Lesechka [4]

Answer:

<u>construction workers</u>

Explanation:

A construction worker is usually someone with the technical skills and abilities needed to manually construct physical infrastructures.

Since a walkway is an infrastructure, hiring skilled construction workers should perform the project of building the series of walkways within the large garden apartment.

3 0
3 years ago
What else will change, if you change the point of view
JulijaS [17]

Answer:

We would need background context,

Explanation:

Then I would be happy to help!

4 0
2 years ago
How to calculate tension.
Evgen [1.6K]

Answer:

Tension can be easily explained in the case of bodies hung from chain, cable, string

Explanation

uniform speed, tension; T = W.

T=m(g±a)

3 0
2 years ago
Ages have been identified by the materials developed and used in those eras.
Westkost [7]
Ok what is the question
6 0
2 years ago
Read 2 more answers
Other questions:
  • Write down a transfer function of a stable system for which pure proportional feedback could drive the system unstable.
    11·1 answer
  • Description: Write a function that takes in a list of numbers and a list of indices. Note that indexList may not only contain va
    8·1 answer
  • A boy weighing 108-lb starts from rest at the bottom A of a 6-percent incline and increases his speed at a constant rate to 7 mi
    11·1 answer
  • Who's your favorite singer and WHT your favorite song​
    11·2 answers
  • A __________ is an added note showing additional or more specific information.
    13·1 answer
  • The coefficient of performance of a reversible refrigeration cycle is always (a) greater than, (b) less than, (c) equal to the c
    12·1 answer
  • Fig. 4 shows a simply-supported beam with supports A and B. The beam is subjected to three forces, 2000 N, 4000 N and 1500 N in
    5·1 answer
  • What is the answer???
    10·1 answer
  • ) A flow is divided into two branches, with the pipe diameter and length the same for each branch. A 1/4-open gate valve is inst
    5·1 answer
  • How old are legos? Who created them? Why did they create them?
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!