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Thermal Efficiency Apparatus

012-05443A

ii

Credits

This manual authored by: Ann Hanks

This manual edited by: Ann Hanks and Eric Ayars

Teacher’s Guide written by: Eric Ayars

Copyright Notice

The PASCO scientific Model TD-8564 Thermal Effi-
ciency Apparatus manual is copyrighted and all rights
reserved.  However, permission is granted to non-profit
educational institutions for reproduction of any part of
this manual providing the reproductions are used only for
their laboratories and are not sold for profit.  Reproduc-
tion under any other circumstances, without the written
consent of PASCO scientific, is prohibited.

Limited Warranty

PASCO scientific warrants this product to be free from
defects in materials and workmanship for a period of one
year from the date of shipment to the customer.  PASCO
will repair or replace, at its option, any part of the product
which is deemed to be defective in material or workman-
ship. This warranty does not cover damage to the product
caused by abuse or improper use.  Determination of
whether a product failure is the result of a manufacturing
defect or improper use by the customer shall be made
solely by PASCO scientific.  Responsibility for the return
of equipment for warranty repair belongs to the customer.
Equipment must be properly packed to prevent damage
and shipped postage or freight prepaid.  (Damage caused
by improper packing of the equipment for return ship-
ment will not be covered by the warranty.)  Shipping
costs for returning the equipment, after repair, will be
paid by PASCO scientific.

Copyright, Warranty and Equipment Return

Please—Feel free to duplicate this manual
subject to the copyright restrictions below.

Equipment Return

Should the product have to be returned to PASCO

scientific for any reason, notify PASCO scientific by

letter, phone, or fax BEFORE returning the product.

Upon notification, the return authorization and

shipping instructions will be promptly issued.

When returning equipment for repair, the units

must be packed properly. Carriers will not accept

responsibility for damage caused by improper

packing. To be certain the unit will not be

damaged in shipment, observe the following rules:

The packing carton must be strong enough for the
item shipped.

Make certain there are at least two inches of
packing material between any point on the
apparatus and the inside walls of the carton.

Make certain that the packing material cannot shift
in the box or become compressed, allowing the
instrument come in contact with the packing
carton.

Address:

PASCO scientific

10101 Foothills Blvd.

Roseville, CA 95747-7100

Phone:

(916) 786-3800

FAX:

(916) 786-3292

email:

[email protected]

web:

www.pasco.com

ä   NOTE:  NO EQUIPMENT WILL BE
ACCEPTED FOR RETURN WITHOUT AN

AUTHORIZATION FROM PASCO.

Содержание TD-8564

Страница 1: ...25 26 27 28 29 30 31 32 C 25 26 27 28 29 30 31 32 K 63 4 60 7 58 1 55 6 53 2 51 0 48 9 46 8 K 63 4 60 7 58 1 55 6 53 2 51 0 48 9 46 8 C 35 36 37 38 39 40 41 42 C 35 36 37 38 39 40 41 42 K 41 2 39 6 37...

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Страница 3: ...of Performance 4 MEASUREMENTS USING THE THERMAL EFFICIENCY APPARATUS Direct Measurements 5 Temperatures 5 Power Delivered to the Hot Reservoir PH 6 Power Dissipated by the Load Resistor PW 6 Indirect...

Страница 4: ...operly packed to prevent damage and shipped postage or freight prepaid Damage caused by improper packing of the equipment for return ship ment will not be covered by the warranty Shipping costs for re...

Страница 5: ...known since the 1800 s but has only become practical since the recent devel opment of semiconductors In 1821 the Russian German physicist Thomas Johann Seebeck discovered that when a junction of diss...

Страница 6: ...gine Introduction Actual Efficiency Carnot Efficiency Measurements Using the Thermal Efficiency Apparatus Direct Measurements Temperatures Power to the Hot Reservoir Power Used by the Load Resistor Ex...

Страница 7: ...es at which energy is transferred or used by the Thermal Efficiency Apparatus all measurements will be power rather than energy So PH dQH dt and then the equation QH W QC becomes PH PW PC and the effi...

Страница 8: ...to do it Notice that although the efficiency is always less than one the COP is always greater than one Maximum Coefficient of Performance As with the maximum efficiency of a heat engine the maximum C...

Страница 9: ...ance of the thermistor imbedded in the hot or cold block To do this connect an ohmmeter to the terminals located as shown in Figure 4 The switch toggles between the hot side and the cold side The ther...

Страница 10: ...culated it is necessary to calculate the internal resistance This is accomplished by measuring the voltage drop across the Peltier device when an external load is applied First run the Thermal Efficie...

Страница 11: ...at which heat is delivered to the hot reservoir PH minus the rate at which work is being done PW Figure 3 Figure 7 No Load The work can be measured directly but the heat delivered to the hot reservoir...

Страница 12: ...experiments are written in worksheet form Feel free to photocopy them for use in your lab NOTE The first paragraph in each experiment lists all the equipment needed to perform the experiment Be sure t...

Страница 13: ...4 Plug the 9V transformer into the wall socket and into the pump on the Thermal Efficiency Apparatus You should now hear the pump running and water should be coming out of the rubber hose marked out P...

Страница 14: ...ch to switch the ohmmeter to each side Record the readings in Table 1 1 Convert the resistances to temperatures using the chart on the front of the device or Table 1 as explained in the Measurements s...

Страница 15: ...actual efficiency increase or decrease as the temperature difference increases The Carnot efficiency represents the best that a perfect heat engine can do Since this heat engine is not perfect the ac...

Страница 16: ...Thermal Efficiency Apparatus 012 05443A 12 Notes...

Страница 17: ...be coming out of the rubber hose marked out Plug the ohmmeter into the thermistor terminals Modes of Operation To obtain all the necessary data for the heat engine it is necessary to run the Thermal E...

Страница 18: ...ents section E Record the voltage VH across the heating resistor the current IH and the voltage across the load resistor VW in Table 2 1 Open A Disconnect the patch cord from the load resistor so no c...

Страница 19: ...adjusted efficiency the total work done in terms of power is PW PW IW 2 r VW 2 R IW 2 r where IW VW R Calculate IW for the 2 load and record in Table 4 B Second the heat input must be adjusted The he...

Страница 20: ...match the Carnot efficiency which assumes no energy loss The adjusted efficiency is eadjusted PW PH PW IW 2 r PH PH open Calculate the internal resistance r using the equation r VP VW VW R which is d...

Страница 21: ...CIENCY experiment to get the data necessary to determine the internal resistance of the Peltier device To complete the measurements for this experiment use the following instructions to run the appara...

Страница 22: ...of Performance Calculate the actual COP using the data taken in the Heat Engine experiment PC PW PH OPEN PW PW Record this result in Table 3 1 Maximum Coefficient of Performance Calculate the maximum...

Страница 23: ...decrease Calculate the rate of change in entropy for the system which includes the hot and cold reservoirs Since the reservoirs are at constant temperature the rate of change in entropy is S t Q t T...

Страница 24: ...al Efficiency Apparatus the Peltier device has 71 couples and each couple consists of 2 elements so there is a total of 142 elements which conduct heat Figure 9 Each element has a length to area ratio...

Страница 25: ...istance of the Peltier device So the power can be expressed in terms of the Seebeck voltage the internal resistance and the load resistance P Vs r R 2 R Assuming the Seebeck voltage remains constant i...

Страница 26: ...ously vary the load resistance However it will be necessary to measure the resistance of the load Allow the system to come to equilibrium so that the hot and cold temperatures are constant This may ta...

Страница 27: ...input to the hot side to keep the temperature of the hot reservoir at the same temperature as it was for the 0 5 resistor while Steps 1 through 6 are repeated for the other possible load resistances...

Страница 28: ...Thermal Efficiency Apparatus 012 05443A 24 Notes...

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