Chemistry, 03.01.2020 05:31, biancabahena04

Aheat pump is used to heat a house in the winter and to cool it in the summer. during the winter, the outside air serves as a low-temperature heat source; during the summer, it acts as a high-temperature heat sink. the heat-transfer rate through the walls and roof of the house is 0.75 kj s—l for each c of temperature difference between the inside and outside of the house, summer and winter. the heat-pump motor is rated at 1.5 kw. determine the minimum outside temperature for which the house can be maintained at 200c during the winter and the maximum outside temperature for which the house can be maintained at 250c during the summer.

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answered: genyjoannerubiera

$T_{C}$ = -4.2°C

$T_{H}$ = 49.4°C

Explanation:

A Carnot cycle is known as an ideal cycle in thermodynamic. Therefore, in theory, we have:

| $\frac{Q_{C} }{Q_{H} }$ | = $\frac{T_{C} }{T_{H} }$

Similarly,

| $Q_{H}$ | = | $Q_{C}$ | + | $W_{S}$ |

During winter, the value of | $T_{H}$ | = 20°C = 273.15 + 20 = 293.15 K and | $W_{S}$ | = 1.5 kW. Therefore,

| $Q_{H}$ | = 0.75( $T_{H}$ - $T_{C}$ )

Similarly,

| $\frac{W_{S} }{Q_{H} }$ | = 1 - $\frac{T_{C} }{T_{H} }$

1.5/0.75*(293.15- $T_{C}$ ) = 1 - ( $T_{C}$ /293.15

Further simplification,

$T_{C}$ = -4.2°C

During summer, $T_{C}$ = 25°C = 273.15+25 = 298.15 K, and | $W_{S}$ | = 1.5 kW. Therefore,

| $Q_{C}$ | = 0.75( $T_{H}$ - $T_{C}$ )

Similarly,

| $\frac{W_{S} }{Q_{C} }$ | = $\frac{T_{H} }{T_{C} }$ - 1

1.5/0.75*( $T_{H}$ - 298.15) = ( $T_{H}$ /298.15

Further simplification,

$T_{H}$ = 49.4°C

answered: Guest

that's just how they are

explanation:

you can't control another persons decisions, all you can do is ask that they respect yours. relationships are hard because you have to put the effort into making sure that another person feels seen, heard, and loved. as time goes on, it gets easier, you learn how to do these things without thinking. loving them becomes as easy as breathing, but every relationship will have fights, and sometimes it'll feel like you're drowning, but as long as you can talk it out and compromise, because that's truly what loving another person is, is compromise, then you'll be okay. movies and tv shows have glamorized and romanticized (pardon the pun) what a relationship would be like. real relationships aren't perfectly timed kisses in the rain, zero fights until one big one ends everything, 6 month anniversaries. real relationships are sleepy confused kisses when one person has to leave for work earlier than the other, real relationships are having small disagreements, real relationships are messy and confusing, real relationships is knowing that even if you're relationship may not last forever and this may not be the person you're going to spend the rest of your life with, that you love them, and you would do anything to see them happy. so yes, relationships are difficult, but so are many other things, relationships can be amazing but also stressful, and not just romantic i'm also talking about platonic relationships (although the primary example here was romantic) sometimes is best to leave friendships behind, so remember, always do whats going to you be happy in the long run.

answered: Guest

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Aheat pump is used to heat a house in the winter and to cool it in the summer. during the winter, th...