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
Afina-wow [57]
3 years ago
13

Estimate the heating energy requirements for a residential building using the degree-day method (a) in Denver, Colorado, and (b)

in Little Rock, Arkansas. The overall heat loss coefficient is 400 Btu/h.oF and the furnace efficiency is 0.78.
Engineering
1 answer:
Lostsunrise [7]3 years ago
5 0

Answer:

a) 600°F  days

b) 103°F  days

Explanation:

Given data :

overall heat loss coefficient = 400 Btu/h.oF

Furnace efficiency = 0.78

applying the degree- day method the heating energy requirement per day can be obtained by subtracting the average temperature for a particular day from the acceptable mid/balance point temperature

lets assume the mid/balance point temperature = 65°F

a) heating energy requirement in Denver Colorado

 we will have 600°F days  ; considering the  the average temperature - balance point temperature

= 665 - 65 = 600°F

b) heating energy requirement in Little Rock Arkansas

 we will have 103°  days

You might be interested in
When _____ ,the lithium ions are removed from the_____ and added into the _____
bezimeni [28]

Answer:

b. Discharging; anode; cathode

Explanation:

When discharging , it means the battery is producing a flow electric current, the lithium ions are released from the  anode to the cathode which generates the flow of electrons from one side to another. When charging Lithium ions are released by the cathode and received by the anode.

8 0
3 years ago
A good rule of thumb is to design the horizontal stabilizer so that its area is about 1/6 to 1/8 of the area of the wing. If the
erik [133]

Answer:

Stabilizer with area = 14 cm2

Explanation:

i dont know why but its right

4 0
3 years ago
The electron concentration in silicon at T = 300 K is given by
puteri [66]

Answer:

E=1.44*10^-7-2.6exp(\frac{-x}{18} )v/m

Explanation:

From the question we are told that:

Temperature of silicon T=300k

Electron concentration n(x)=10^{16}\exp (\frac{-x}{18})

                                        \frac{dn}{dx}=(10^{16} *(\frac{-1}{16})\exp\frac{-x}{16})

Electron diffusion coefficient is Dn = 25cm^2/s \approx 2.5*10^{-3}

Electron mobility is \mu n = 960 cm^2/V-s \approx0.096m/V

Electron current density Jn = -40 A/cm^2 \approx -40*10^{4}A/m^2

Generally the equation for the semiconductor is mathematically given by

Jn=qb_n\frac{dn}{dx}+nq \mu E

Therefore

-40*10^{4}=1.6*10^{-19} *(2.5*10^{-3})*(10^{16} *(\frac{-1}{16})\exp\frac{-x}{16})+(10^{16}\exp (\frac{-x}{18}))*1.6*10^{-19}*0.096* E

E=\frac{-2.5*10^-^7 exp(\frac{-x}{18})+40*10^{4}}{1.536*10^-4exp(\frac{-x}{18} )}

E=1.44*10^-7-2.6exp(\frac{-x}{18} )v/m

7 0
3 years ago
Air enters a 34 kW electrical heater at a rate of 0.8 kg/s with negligible velocity and a temperature of 60 °C. The air is disch
Flura [38]

Answer:

79 kW.

Explanation:

The equation for enthalpy is:

H2 = H1 + Q - L

Enthalpy is defined as:

H = G*(Cv*T + p*v)

This is specific volume.

The gas state equation is:

p*v = R*T (with specific volume)

The specific gas constant for air is:

287 K/(kg*K)

Then:

T1 = 60 + 273 = 333 K

T2 = 200 + 273 = 473 K

p1*v1 = 287 * 333 = 95.6 kJ/kg

p2*v2 = 287 * 473 = 135.7 kJ/kg

The Cv for air is:

Cv = 720 J/(kg*K)

So the enthalpies are:

H1 = 0.8*(0.72 * 333 + 95.6) = 268 kW

H2 = 0.8*(0.72 * 473 + 135.7) = 381 kW

Ang the heat is:

Q = 34 kW

Then:

H2 = H1 + Q - L

381 = 268 + 34 - L

L = 268 + 34 - 381 = -79 kW

This is the work from the point of view of the air, that's why it is negative.

From the point of view of the machine it is positive.

4 0
4 years ago
A(n) BLANK authenticates various specimens in a collection for a museum.
mezya [45]

Answer:

Curators

Explanation:

4 0
3 years ago
Other questions:
  • The steel shaft has a radius of 15 mm. Determine the torque Tin the shaft if the two strain gages, attached to the surface of th
    13·1 answer
  • Electricity is generated in two forms namely………A. Alternating current and wave form B. Alternating current and basic current C.
    7·2 answers
  • As an input signal drives the base voltage in a positive direction, base current will_____ and collector current will _____.
    5·1 answer
  • Your manager has asked you to research and recommend a writing guide that examiners in your digital forensics company can use fo
    8·1 answer
  • A. The temperature of a system is measured to be 75 °F. Express this temperature in °C, K, and R.
    9·1 answer
  • How many seconds will it take to cross the street at a normal walking pace?
    15·1 answer
  • g A motor driving a 1000-W water pump has a power factor of 0.80 lagging; a second motor driving a 600-W water pump has a power
    15·1 answer
  • Let S = { p q |p, q are prime numbers greater than 0} and E = {0, −2, 2, −4, 4, −6, 6, · · · } be the set of even integers. . Pr
    6·1 answer
  • I’ll give you 100 points
    10·2 answers
  • ceramics must be heated in order to harden the clay and make it durable. the equipment used to heat the clay
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!