ENGINEERING FUNDAMENTALS
ENGINEERING FUNDAMENTALS
6th Edition
ISBN: 9781337705011
Author: MOAVENI
Publisher: CENGAGE L
Question
Book Icon
Chapter 11, Problem 41P
To determine

Calculate the amount of natural gas required to heat the water in a heater.

Expert Solution & Answer
Check Mark

Answer to Problem 41P

The amount of natural gas required to heat the water in a heater is 72ft3day.

Explanation of Solution

Given data:

Volume of water used per day is 80gallons,

Initial temperature of water is, Tinitial=55°F,

Final temperature of water is, Tfinal=140°F,

Efficiency of heater is 80%,

From Table 11.13 in the textbook, the specific heat of water is, c=4180JkgK,

Standard density of water is 1000kgm3.

Formula used:

The relationship between degree Fahrenheit and degree Celsius is,

T(°C)=59[T(°F)32] (1)

Here,

T(°C) is the temperature in degree Celsius,

T(°F) is the temperature in degree Fahrenheit.

The formula to find thermal energy required to heat the water is,

Ethermal=mc(TfinalTinitial) (2)

Here,

m is the mass of the water,

c is the specific heat of water,

Tinitial is the initial temperature of water,

Tfinal is the final temperature of water.

Calculation:

Convert the unit of volume of the water,

Volume=80gallonsday[1gallon=3.7854×103m3]=(80gallonsday)(3.7854×103m31gallon)=(80×3.7854×103)m3dayVolume=0.3028m3day

Substitute 55°F for T(°F) in equation (1) to get the initial temperature in degree Celsius,

Tinitial(°C)=59[5532]=12.77°C

Substitute 140°F for T(°F) in equation (1) to get the final temperature in degree Celsius,

Tfinal(°C)=59[14032]=60°C

The expression to find the mass of the water is,

Mass=Volume×density=(0.3028m3day)(1000kgm3)Mass=302.8kgday

Substitute 302.8kgday for m, 4180JkgK for c, 12.77°C for Tinitial, and 60°C for Tfinal in equation (2) to find Ethermal,

Ethermal=(302.8kgday)(4180JkgK)(60°C12.77°C)      [ °C=K]=(302.8kgday)(4180JkgK)(6012.77)K

Ethermal=59.7792×106Jday

The unit conversion on above result is,

Ethermal=59.7792×106Jday[1day=24h]=59.7792×106(Jday×1day24h)[1h=3600s]=(2.491×106Jh)(1h3600s)[1Js=1W]Ethermal=693W

Do the unit conversion on above result,

Ethermal=693W[1W=3.412Btuh]=(693W)(3.412Btuh1W)Ethermal=2364.6Btuh

At standard 77°F temperature, the heating value of methane is 978Btuft3. Since the major composition of natural gas is methane, consider the heating value of natural gas is 978Btuft3, as the range of temperature given as 55°F to 140°F considered for 77°F.

Then the amount of natural gas required to heat the water in heater can be determined from the below expression:

Volumeofgas=EthermalEfficiency×Heatingvalueofgas=2364.6Btuh0.8(978Btuft3)[1day=24h]=(3ft3h)(24h1day)Volumeofgas=72ft3day

Therefore, the amount of natural gas required to heat the water in a heater is 72ft3day.

Conclusion:

Hence, the amount of natural gas required to heat the water in a heater is 72ft3day.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
As a strategy of the Salahadin Government to extend the residency community in Tikrit City, there is a plan to provide water for a new residential area on the west side of Tikrit City, as shown in the map in Figure 1. The new residential area is exposed to have 25000 residences, three schools to serve 1000 students, and a Plaza Markt that can serve 2000 persons. The water will be supplied from a purification station installed on the Tigris River at an elevation equal to 130 m. The distance between the water purification station and the center of the new residential area is about 9.5 km, and the elevation of the city center is about 150 m. The required pressure in the new residential area center is 30 m. The available pipes in the market with their price are shown in Table 1. Also, the price for each 10-meter of pump head is 1500$. Your task as environmental engineers is to design a sustainable and economically viable water system, including the main pipeline and pump for the new…
Find the volume of the following a. 5" cube b. 10' of 8" pipe
(5) The simply supported beam shown in figure supports uniformly distributed characteristicdead and imposed loads of 5 kNm-1 each, as well as a characteristic imposed point load of 30 kN at mid-span. Assuming the beam is fully laterally restrained and there is nominaltorsional restrain at supports, select a suitable UB section in S275 steel to satisfy bendingand shear considerations. Also, check the selected UB section against the deflection.           (40 Marks)

Chapter 11 Solutions

ENGINEERING FUNDAMENTALS

Knowledge Booster
Background pattern image
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Engineering Fundamentals: An Introduction to Engi...
Civil Engineering
ISBN:9781305084766
Author:Saeed Moaveni
Publisher:Cengage Learning
Text book image
Sustainable Energy
Civil Engineering
ISBN:9781337551663
Author:DUNLAP, Richard A.
Publisher:Cengage,
Text book image
Sustainable Energy
Civil Engineering
ISBN:9781133108689
Author:Richard A. Dunlap
Publisher:Cengage Learning
Text book image
Solid Waste Engineering
Civil Engineering
ISBN:9781305635203
Author:Worrell, William A.
Publisher:Cengage Learning,