Experimental Facility for the Study of Enhanced Refrigerants

MEMS 1042 Semester Project

Stanley Schurdak

Project Overview

MotivationReduce annual energy cost from domestic refrigerators

Use enhanced refrigerants to reduce compressor cycle time

Shorter run time lowers energy consumption

ScopeRefrigerants with large cp-values increase heat transfer rate

Experimental facility is needed to quantify cp- values

Improved cp-values can be related to COP and cost savings

Defining Equations

Constant-pressure specific heat (cp)

Coefficient of performance ( )

Energy consumption (E)

=q  Lw  c

: Heat transfer rate: Refrigerant mass flow rate

T: Refrigerant temperature change

: Heat transfer rate: Compressor work

: Compressor work t : Compressor cycle time

Specific Heat Target Range

Common Refrigerants

Improved RefrigerantsFor significant savings, process cp must be 2 4 times higher

Expected range is 1.29 17.50 kJ/kg-K

Experimental facility must be designed accordingly

Refrigerant cp (-23ºC, 120 kPa) cP (Process: -23ºC 32ºC)

R-22 0.628 kJ/kg-K 0.646 kJ/kg-K

R-410a 0.788 kJ/kg-K 0.806 kJ/kg-K

R-134a 1.287 kJ/kg-K 4.735 kJ/kg-K

Basic Construction

Experimental SetupWooden crate with rigid insulation covering

Copper pipes assembled to form condenser/evaporator

Flow meter and thermocouple output to PC via DAQ

Estimated CostWood/Insulation: ~$62.73

Piping/Connections: ~$71.07

Compressor/Expansion Valve: ~$249.46

Experimental Facility

SchematicFacility consists of compressor, condenser, expansion valve, and evaporator

Components connected with copper tubing

Experimental Facility

Model

Evaporator coils

Thermocouples insertedthrough walls(not shown)

Expansion valve/flow meter assembly(not shown)

Compressor(not shown)Condenser coils

Thermocouples attached to pipes(not shown)

Sensors

Proposal AMax Machinery Piston Flow Meter 214

Accuracy: 0.2% of reading

Cost: $2450.00

Fieldpiece Clamp Thermocouple ATC1R (x2)Accuracy: 0.5ºC

Cost: $93.18

Omega Thermocouple 5TC-PVC-K-24-180Accuracy: 1.5ºC

Cost: $55.00

Sensors

Proposal BDwyer MFS2-2 Flow Meter

Accuracy: 1.0% of reading

Cost: $679.00

StopwatchesUSA Combination Thermometer/Timer (x4)Accuracy: 1.0ºC/ 1.0 Sec

Cost: $40.00

Total Sensor Cost/Overall AccuracyProposal A: $2917.18, cp 3.16%, 2.73%

Proposal B: $1037.80, cp 3.45%, 2.89%

Summary

Accuracy/Cost Comparison

Proposal A Proposal B

Materials: $423.26 $423.26

Sensors: $2917.18 $1037.80

Total Cost: $3340.44 $1412.06

Accuracy: cp 3.16%, 2.73% cp 3.45%, 2.89%

Pros: Higher accuracy; digital output allows for datastorage and analysis

Simple setup; data from only mass flow needs to be

recorded; less expensive

Cons: More expensive; flow meter could be difficult

to work with

Slightly less accurate; thermometers/timers could be inaccurate

Questions?

Specific Heat Uncertainty

0.1

0.2

0.3

0.4

0.5

0.6

0.7

8 13 18 23

Un

cert

ain

ty (k

J/kg

-K)

Specific Heat (kJ/kg-K)

ucp vs. cp

Option A

Option B

3.443.443.443.443.443.453.453.453.45

8 13 18 23

Pee

rcen

t Un

cert

ain

ty

Specific Heat (kJ/kg-K)

%ucp vs. cp

Option B

3.173.173.173.173.173.173.173.173.17

8 13 18 23

Pee

rcen

t Un

cert

ain

ty

Specific Heat (kJ/kg-K)

%ucp vs. cp

Option A

COP Uncertainty

0.0480.0580.0680.0780.0880.0980.1080.1180.1280.1380.148

2 3 4 5

Un

cert

ain

ty (k

W/k

W)

(kW/kW)

u vs.

Option A

Option B

2.732.732.732.732.732.732.732.732.732.73

2 3 4 5

Per

cen

t Un

cert

ain

ty

COP (kW/kW)

%u vs.

Option A

2.882.882.892.892.892.892.892.902.902.90

2 3 4 5

Per

cen

t Un

cert

ain

ty

(kW/kW)

%u vs.

Option B

Bill of Materials

Sensor Vendor Model PriceRefrigerant Thermocouple (x2) Fieldpiece ATC1R $93.18 Box Thermocouple (x5) Omega 5TC-PVC-K-24-180 $55.00 Flow Meter Max Machinery 214 Analog $2450.00DAQ NI USB-6525 $319.00

Total Sensors: $2,917.18

Part Vendor Model PriceCompressor Samsung MK183C-L2U $151.85 Copper pipe 1/4" (50') Lowe's D 04050PS $31.07 Copper pipe 3/8" (50') D 06050PSE $49.00 Misc. Connectors Lowe's N/A $40.00 Expansion Valve Randell RF-VLV200 $97.61 Wood 2 x 4 (x3) Home Depot 161640 $8.94 Plywood (x2) Home Depot 646214 $16.16 Insulation (x2) Home Depot 45W $28.63

Total Parts: $423.26

Grand Total: $3340.44

Option A

Bill of Materials

Sensor Vendor Model PriceThermometer/Timer (x4) StopwatchesUSA 41100A $40.00 Flow Meter Dwyer MFS2-2 $625.00 Flow Meter Cable Dwyer MFS-C3 $54.00 DAQ NI USB-6525 $319.00

Total Sensors: $1037.80

Part Vendor Model PriceCompressor Samsung MK183C-L2U $151.85 Copper pipe 1/4" (50') Lowe's D 04050PS $31.07 Copper pipe 3/8" (50') Lowe's D 06050PSE $49.00 Misc. Connectors Lowe's N/A $40.00 Expansion Valve Randell RF-VLV200 $97.61 Wood 2 x 4 (x3) Home Depot 161640 $8.94 Plywood (x2) Home Depot 646214 $16.16 Insulation (x2) Home Depot 45W $28.63

Total Parts: $423.26

Grand Total: $1461.06

Option B

Uncertainty Equations

=q  Lw  c

w  c

= q  Lw  c

2

q  L

=1w  c

u =uq  Lw  c

÷

2

+ q  Luw  cw  c

2

÷

2

Uncertainty Equations

References

Fatouh, M., and M. El Kafafy. "Experimental Evaluation of a Domestic Refrigerator Working with LPG B.V., Oct. 2006. Web. 29 Mar. 2014.

Sonntag, Richard Edwin., C. Borgnakke, Van Wylen Gordon J., and Van WylenGordon J. Fundamentals of Thermodynamics. New York: Wiley, 2003. Print.

Equation Partials Uncertainty !Air - u!Air = ±0.0005 kg/m3

cp Air - uCp Air = ±0.0005 kJ/kg-K

VAir = LAir WAir HAir

!

"VAir

"LAir=WAirHAir

"VAir

"WAir

= LAirHAir

"VAir

"HAir

= LAirWAir

!

uVAir = uL (WAirHAir)2 + (LAirHAir)

2 + (LAirWAir)2

!

TAir =T1 +T2 +T3 +T4 +T5

5

!

"#TAir"T1

="#TAir"T2

="#TAir"T3

="#TAir"T4

="#TAir"T5

=15

!

uTAir =uT5

!TAir = Tf - Ti

!

"#TAir"Tf

=1

"#TAir"Ti

= $1

!

u"TAir =uTAir2

!t - u"t = ±1 sec

!

˙ m -

!

u ˙ m = ±0.2%

!TR = TR2 – TR1

!

"#TR"TR2

=1

"#TR"TR1

= $1

!

u"TR =uTR2

!

˙ q L ="AirVAirc pAir#TAir

#t

!

" ˙ q L"#Air

=VAircpAir$TAir

$t" ˙ q L"VAir

=#Airc pAir$TAir

$t" ˙ q L"cpAir

=#AirVAir$TAir

$t

" ˙ q L"$TAir

=#AirVAirc pAir

$t" ˙ q L"$t

=%#AirVAirc pAir$TAir

$t 2

!

u ˙ q L=

VAircpAir"TAir

"tu#Air

$

% &

'

( )

2

+#Airc pAir"TAir

"tuVAir

$

% &

'

( )

2*

+ , ,

!

+VAir"Air#TAir

#tucpAir

$

% &

'

( ) 2

+VAir"Airc pAir

#tu#TAir

$

% &

'

( )

2

!

+"VAir#Airc pAir$TAir

$t 2u$tAir

%

& '

(

) *

2 +

, - -

12

!

cp =˙ q L

˙ m "TR

!

"cp

" ˙ q L=

1˙ m #TR

"cp

" ˙ m =

$ ˙ q L˙ m 2#TR

"cp

"#TR

=$ ˙ q L

˙ m #TR2

!

ucp =u ˙ q L

˙ m "T#

$ %

&

' (

2

+˙ q Lu ˙ m

˙ m 2"T#

$ %

&

' (

2

+˙ q Lu"T

˙ m "T 2

#

$ %

&

' (

2

!

˙ w c -

!

u ˙ w c =0.0005 kJ

!

" =˙ q L˙ w c

!

"#" ˙ w c

=$ ˙ q L˙ w c

2

"#" ˙ q L

=1˙ w c

!

u" =u ˙ q L

˙ w c

#

$ %

&

' (

2

+) ˙ q Lu ˙ w c

˙ w c2

#

$ %

&

' (

2

!

E = ˙ w c"t

!

"E" ˙ w c

= #t

"E"#t

= ˙ w c

!

uE = "tu ˙ w c( )2+ ˙ w cu"t( )2