What type of intersection is this?

A heat pump receives heat from a lake that has an average wintertime temperature of 6o C and supplies heat into a house having a

Dafna1 [17]

Answer:

a) $\dot W = 1.062\,kW$

Explanation:

a) Let consider that heat pump is reversible, so that the Coefficient of Performance is:

$COP_{HP} = \frac{T_{H}}{T_{H}-T_{L}}$

$COP_{HP} = \frac{298.15\,K}{298.15\,K-279.15\,K}$

$COP_{HP} = 15.692$

The minimum heat received by the house must be equal to the heat lost to keep the average temperature constant. Hence:

$\dot Q_{H} = 60000\,\frac{kJ}{h}$

The minimum power supplied to the heat pump is:

$\dot W = \frac{\dot Q_{H}}{COP}$

$\dot W = \frac{\left(60000\,\frac{kJ}{h} \right)\cdot \left(\frac{1\,h}{3600\,s} \right)}{15.692}$

$\dot W = 1.062\,kW$

5 0

3 years ago

When do design engineers start on the design improvement step?

ArbitrLikvidat [17]

Answer:

as soon as there is a design to improve

Explanation:

As a design engineer, I started on the "design improvement" step as soon as I had an initial conceptual design.

__

Then, I started that step again when my boss told me, "make it better."

_____

The more interesting question is, "when do you <em>stop</em> the design improvement step?" (Judging by the constant barrage of software updates, that answer is, "never.")

8 0

3 years ago

4. Training is an important way to keep yourself and others safe while at work.

Gekata [30.6K]

it's answer is true.

hope...it's helpful.

7 0

2 years ago

Read 2 more answers

An inductor is connected to a voltage source and it is found that it has a time constant, t. When a 10-ohm resistor is placed in

prisoha [69]

Answer:

A) 30 mH

B ) 10-ohm

Explanation:

resistor = 10-ohm

Inductor = 30mH ( l )

L = inductance

R = resistance

r = internal resistance

values of the original Inductors

Note : inductor = constant time (t) case 1

inductor + 10-ohm resistor connected in series = constant time ( t/2) case2

inductor + 10-ohm resistor + 30 mH inductance in series = constant time (t) case3

<em>From the above cases</em>

case 1 = time constant ( t ) = L / R

case 2 = Req = R + r hence time constant t / 2 = L / R + r therefore

t = $\frac{2L}{R+r}$

case 3 = Leq = L + l , Req = R + r . constant time ( t )

hence Z = $\frac{L + l}{R + r}$ = t

A) Inductance

To calculate inductance equate case 1 to case 3

$\frac{L}{R}$ = $\frac{L + l}{R + r}$ = L / 10 = (L + 30) / ( 10 + 10 )

= 20 L = 10 L + 300 mH

10L = 300 m H

therefore L = 30 mH

B ) The internal resistance

equate case 1 to case 2

$\frac{L}{R}$ = $\frac{2L}{R + r}$

R + r = 2 R therefore ( r = R ) therefore internal resistance = 10-ohm

6 0

3 years ago

The relationship between the pressure drop per unit length along a smooth-walled, horizontal microfluidic channel and the variab

MA_775_DIABLO [31]

Answer:

Δp = ∫ $( D, p, u, V)$

Explanation:

The pressure drop formula is given above. It determines the relation between pressure drop per unit along with smooth walled channel. The formula is from Buckingham pi theorem in which repeating and non repeating variables are used together.

7 0

3 years ago