I know My Professional Community(Engineers) will love this : GMAT Reading Comprehension (RC)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 18 Jan 2017, 03:10

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# I know My Professional Community(Engineers) will love this

Author Message
TAGS:

### Hide Tags

Director
Joined: 04 Jan 2008
Posts: 912
Followers: 69

Kudos [?]: 572 [2] , given: 17

I know My Professional Community(Engineers) will love this [#permalink]

### Show Tags

28 Mar 2009, 04:15
2
KUDOS
I know My Professional Community(Engineers) will love this passage
========
The use of heat pumps has been held back largely by skepticism about advertisers’ claims that heat pumps can provide as many as two units of thermal energy for each unit of electrical energy used, thus apparently contradicting the principle of energy conservation. Heat pumps circulate a fluid refrigerant that cycles alternatively from its liquid phase to its vapor phase in a closed loop. The refrigerant, starting as a low-temperature, low-pressure vapor, enters a compressor driven by an electric motor. The refrigerant leaves the compressor as a hot, dense vapor and flows through a heat exchanger called the condenser, which transfers heat from the refrigerant to a body of air. Now the refrigerant, as a high-pressure, cooled liquid, confronts a flow restriction which causes the pressure to drop. As the pressure falls, the refrigerant expands and partially vaporizes, becoming chilled. It then passes through a second heat exchanger, the evaporator, which transfers heat from the air to the refrigerant, reducing the temperature of this second body of air. Of the two heat exchangers, one is located inside, and the other one outside the house, so each is in contact with a different body of air: room air and outside air, respectively.

The flow direction of refrigerant through a heat pump is controlled by valves. When the refrigerant flow is reversed, the heat exchangers switch function. This flow-reversal capability allows heat pumps either to heat or cool room air. Now, if under certain conditions a heat pump puts out more thermal energy than it consumes in electrical energy, has the law of energy conservation been challenged? No, not even remotely: the additional input of thermal energy into the circulating refrigerant via the evaporator accounts for the difference in the energy equation.

Unfortunately, there is one real problem. The heating capacity of a heat pump decreases as the outdoor temperature falls. The drop in capacity is caused by the lessening amount of refrigerant mass moved through the compressor at one time. The heating capacity is proportional to this mass flow rate: the less the mass of refrigerant being compressed, the less the thermal load it can transfer through the heat-pump cycle. The volume flow rate of refrigerant vapor through the single-speed rotary compressor used in heat pumps is approximately constant. But cold refrigerant vapor entering a compressor is at lower pressure than warmer vapor. Therefore, the mass of cold refrigerant—and thus the thermal energy it carries—is less than if the refrigerant vapor were warmer before compression.

Here, then, lies a genuine drawback of heat pumps: in extremely cold climates—where the most heat is needed—heat pumps are least able to supply enough heat.

17. The primary purpose of the passage is to

(A) explain the differences in the working of a heat pump when the outdoor temperature changes
(B) contrast the heating and the cooling modes of heat pumps
(C) describe heat pumps, their use, and factors affecting their use
(E) expose extravagant claims about heat pumps as false

18. The author resolves the question of whether heat pumps run counter to the principle of energy conservation by

(A) carefully qualifying the meaning of that principle
(B) pointing out a factual error in the statement that gives rise to this question
(D) denying the relevance of that principle to heat pumps
(E) explaining that heat pumps can cool, as well as heat, room air

19. It can be inferred from the passage that, in the course of a heating season, the heating capacity of a heat pump is greatest when

(A) heating is least essential
(B) electricity rates are lowest
(C) its compressor runs the fastest
(E) the heating demand surges

20. If the author’s assessment of the use of heat pumps (lines 1-6) is correct, which of the following best expresses the lesson that advertisers should learn from this case?

(A) Do not make exaggerated claims about the products you are trying to promote.
(C) Do not use facts in your advertising that will strain the prospective client’s ability to believe.
(D) Do not assume in your advertising that the prospective clients know even the most elementary scientific principles.
(E) Concentrate your advertising firmly on financially relevant issues such as price discounts and efficiency of operation.

21. The passage suggests that heat pumps would be used more widely if

(A) they could also be used as air conditioners
(B) they could be moved around to supply heat where it is most needed
(C) their heat output could be thermostatically controlled
(D) models with truly superior cooling capacity were advertised more effectively
(E) people appreciated the role of the evaporator in the energy equation

22. According to the passage, the role of the flow restriction (lines 16-17) in a heat pump is to

(A) measure accurately the flow rate of the refrigerant mass at that point
(B) compress and heat the refrigerant vapor
(C) bring about the evaporation and cooling of refrigerant
(D) exchange heat between the refrigerant and the air at that point
(E) reverse the direction of refrigerant flow when needed

23. The author regards the notion that heat pumps have a genuine drawback as a

(A) cause for regret
(B) sign of premature defeatism
(C) welcome challenge
(D) case of sloppy thinking
(E) focus for an educational campaign
================
_________________

http://gmatclub.com/forum/math-polygons-87336.html
http://gmatclub.com/forum/competition-for-the-best-gmat-error-log-template-86232.html

If you have any questions
New!
Director
Joined: 25 Oct 2006
Posts: 648
Followers: 13

Kudos [?]: 506 [0], given: 6

Re: Long RC 1-Science(Heat Pump) Passage-Saturday [#permalink]

### Show Tags

28 Mar 2009, 11:59
I would go with C, C, A, C, E, C, A
_________________

If You're Not Living On The Edge, You're Taking Up Too Much Space

VP
Joined: 05 Jul 2008
Posts: 1430
Followers: 39

Kudos [?]: 360 [0], given: 1

Re: Long RC 1-Science(Heat Pump) Passage-Saturday [#permalink]

### Show Tags

28 Mar 2009, 15:20
14 min

Got C C A C A C A

I have a funny feeling about all C's and A's.
Current Student
Joined: 13 Jan 2009
Posts: 372
Location: India
Followers: 20

Kudos [?]: 120 [0], given: 1

Re: Long RC 1-Science(Heat Pump) Passage-Saturday [#permalink]

### Show Tags

28 Mar 2009, 15:41
18 mins

Director
Joined: 04 Jan 2008
Posts: 912
Followers: 69

Kudos [?]: 572 [0], given: 17

Re: Long RC 1-Science(Heat Pump) Passage-Saturday [#permalink]

### Show Tags

28 Mar 2009, 23:02
15 mins
was not sure abt last one and no 20
applied poe in 23
_________________

http://gmatclub.com/forum/math-polygons-87336.html
http://gmatclub.com/forum/competition-for-the-best-gmat-error-log-template-86232.html

Director
Joined: 04 Jan 2008
Posts: 912
Followers: 69

Kudos [?]: 572 [0], given: 17

Re: Long RC 1-Science(Heat Pump) Passage-Saturday [#permalink]

### Show Tags

28 Mar 2009, 23:03
Wow!!
OAs are same
priyankur_saha@ml.com wrote:
I would go with C, C, A, C, E, C, A

_________________

http://gmatclub.com/forum/math-polygons-87336.html
http://gmatclub.com/forum/competition-for-the-best-gmat-error-log-template-86232.html

Director
Joined: 25 Oct 2006
Posts: 648
Followers: 13

Kudos [?]: 506 [0], given: 6

Re: Long RC 1-Science(Heat Pump) Passage-Saturday [#permalink]

### Show Tags

28 Mar 2009, 23:20
icandy wrote:
14 min

Got C C A C A C A

I have a funny feeling about all C's and A's.

Agree, I felt that I was doing wrong.
_________________

If You're Not Living On The Edge, You're Taking Up Too Much Space

VP
Joined: 18 May 2008
Posts: 1286
Followers: 16

Kudos [?]: 411 [0], given: 0

Re: Long RC 1-Science(Heat Pump) Passage-Saturday [#permalink]

### Show Tags

29 Mar 2009, 22:31
LAte but here r my answers:
CCACCCA

Confused in Q21, can anyone explain it? I thought its already behaving like an AC "This flow-reversal capability allows heat pumps either to heat or cool room air."
Senior Manager
Joined: 04 Sep 2008
Posts: 259
Location: Kolkata
Schools: La Martiniere for Boys
Followers: 2

Kudos [?]: 90 [0], given: 9

Re: Long RC 1-Science(Heat Pump) Passage-Saturday [#permalink]

### Show Tags

17 Apr 2009, 22:48
PRIYANKUR,

_________________

Thanks
rampuria

Senior Manager
Joined: 26 Mar 2008
Posts: 337
Location: Washington DC
Followers: 2

Kudos [?]: 76 [0], given: 4

Re: Long RC 1-Science(Heat Pump) Passage-Saturday [#permalink]

### Show Tags

20 Apr 2009, 12:20
It took me around 17 minutes.. and answers-
1 C 05:27
2 C 01:13
3 A 02:03
4 C 03:19
5 C 01:15
6 B 01:23 doubt
7 A 02:06

Now since OA is out I know what why my 5question is wrong. Thanks for the post.
Intern
Joined: 03 Jun 2009
Posts: 30
Followers: 2

Kudos [?]: 12 [0], given: 1

Re: Long RC 1-Science(Heat Pump) Passage-Saturday [#permalink]

### Show Tags

01 Jul 2009, 07:00
Manager
Joined: 24 Apr 2009
Posts: 93
Followers: 2

Kudos [?]: 14 [0], given: 2

Re: Long RC 1-Science(Heat Pump) Passage-Saturday [#permalink]

### Show Tags

09 Jul 2009, 09:24
jaxtor wrote:

see the last 2 lines of the passage.. they say that when heating is needed, the heat pump heats less i.e. when the temperature is cooler. So conversely, when heating is needed least, the pumps will be more efficient..
Director
Joined: 05 Jun 2009
Posts: 849
WE 1: 7years (Financial Services - Consultant, BA)
Followers: 11

Kudos [?]: 310 [0], given: 106

Re: Long RC 1-Science(Heat Pump) Passage-Saturday [#permalink]

### Show Tags

18 Jul 2009, 12:01
ECAAECA

Time: 12:57

2 wrong though
_________________

Consider kudos for the good post ...
My debrief : http://gmatclub.com/forum/journey-670-to-720-q50-v36-long-85083.html

Director
Joined: 01 Aug 2008
Posts: 768
Followers: 4

Kudos [?]: 625 [0], given: 99

Re: Long RC 1-Science(Heat Pump) Passage-Saturday [#permalink]

### Show Tags

17 Aug 2009, 18:51
c c a e c e a -- 3 wrongs
Director
Joined: 01 Aug 2008
Posts: 768
Followers: 4

Kudos [?]: 625 [0], given: 99

Re: Long RC 1-Science(Heat Pump) Passage-Saturday [#permalink]

### Show Tags

17 Aug 2009, 18:54
jaxtor wrote:

when outside heat is more then it generates more heat as well. so when it is hot out side, you really don't need more heat, isn't it?
Current Student
Joined: 26 Jan 2013
Posts: 22
GMAT 1: 680 Q49 V33
Followers: 0

Kudos [?]: 11 [0], given: 86

Re: I know My Professional Community(Engineers) will love this [#permalink]

### Show Tags

06 Oct 2014, 03:16
Can anyone explain 19,21 and 23?
Re: I know My Professional Community(Engineers) will love this   [#permalink] 06 Oct 2014, 03:16
Similar topics Replies Last post
Similar
Topics:
I am working on my RC skills but as all of you know time is 5 12 Mar 2012, 21:06
I know for the other sections it's easy to hard. Is that 1 27 Jul 2011, 17:31
i know, some discuss this problem before, but I haven't got 2 02 Sep 2010, 08:13
3 Ohh I love Dinosaurs hence this passage 18 30 Mar 2009, 08:12
Dear Friends, I would like to know following while 2 05 Jan 2008, 23:05
Display posts from previous: Sort by