K1 amath Fa1 Is, Oregon

I

GEOTHERMAL SPACE AND WATER HEATING FACILITIES School e r Apartments

K1

amath Fa1 I s , Oregon

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DISCLAIMER

This r e p o r t was prepared as an account o f work sponsored by t h e United States Government. Neither the United States n o r t h e United States Department o f Energy, nor any o f t h e i r employees

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n o r any o f t h e i r contractors, subcontractors

,

o r t h e i r employees, makes any warranty, expressed o r implied, o r assumes any 1 egal 1 i abi 1 i t y o r responsi b i 1 i t y f o r t h e accuracy

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7

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GEOTHERMAL SPACE AND WATER HEATING FACILITIES Schooler Apartments

K1 amath Fa1 1

s ,

^Oregon

The following f e a s i b i l i t y study i s the r e s u l t o f a request t o t h e Geo-Heat U t i 1 i z a t i o n Center f o r Technical Assistance.

I n t r o d u c t i o n

comprising a t o t a l o f 16 apartments o f about 1000 square f e e t each. The plan c a l l s f o r t h e construction o f e i g h t buildings w i t h a t o t a l of 50 apartments.

j u s t west o f Summers Lane,. Mr. Schooler i s considering heating t h e

apartments w i t h i n d i v i d u a l 10 KW e l e c t r i c furnaces, and providing domestic h o t water w i t h e l e c t r i c water heaters. As an a l t e r n a t i v e , he has requested a study t o determine t h e f e a s i b i l i t y of u t i l i z i n g geothermal water f o r space and domestic water heating.

M r . Roger Schooler presently has under construction two b u i l d i n g s

The complex i s located on the n o r t h < s i d e o f H i l y a r d Avenue

Summary and Conclusion

1. U t i l i z i n g geothermal water f o r space and water heating of t h e 50 apartment b u i l d i n g s i s f e a s i b l e and economically a t t r a c t i v e . Estimated i n s t a l l e d cost f o r t h e f a c i l i t i e s i s $130,000. The n e t c a p i t a l c o s t t o the p r o j e c t i s $103,000, when a c r e d i t o f $27,000 i s taken f o r e l e c t r i c furnaces and water heaters n o t i n s t a l l e d . Table 1 presents a summary o f the c a p i t a l costs. Based on the $103,000 a 31% r a t e o f return, a f t e r taxes, has been c a l c u l ated.

2.

operation i s calculated t o be $39,333.

r e n t a l charge would be required. A charge o f $65 a month per apartment would be approximately equal t o t h i s energy savings.

analysis an i n i t i a l t o t a l income o f $37,366 was used. This i s based on 95% occupancy. Table 2 summarizes how income was determined.

3.

r e n t a l premium o f $65 per month was increased by 7% per year.

energy costs are forecasted ^€0 escalate a t 9.5% per year through 1986, and 8.58% per year t h e r e a f t e r .

premium charge on t h e apartments could be greater i n l a t e r years than those developed using the 7% figure. A s a t i s f a c t o r y r a t e o f r e t u r n on c a p i t a l could be projected by using a lower i n i t i a l r e n t a l premium, and a r e n t a l premium escalation r a t e higher than 7%. I n i t i a l operating costs amount t o $6,036 p e r year f o r maintenance, e l e c t r i c i t y f o r pumping,

taxes, and insurance. Depreciation amounts t o $4,635 per year. Table 3 sumnarizes operating costs.

Savings i n e l e c t r i c a l power consumption f o r the f i r s t f u l l year of To generate income a premium

For the cost

I n determining the 31% r a t e o f r e t u r n on invested c a p i t a l , the i n i t i a l E l e c t r i c a l Based on these percentages, t h e allowable

,.

We1 1

s

An e x i s t i n g 500 f o o t w e l l e x i s t s on the property. Temperature measure- ments taken on J u l y 3, 1979 indicated the bottom temperature t o be 98OF, a t a depth o f about 450 feet. Apparently there was a cave-in o r blockage a t t h a t l e v e l . E a r l i e r data (Water Resources I n v e s t i g a t i o n 76-127, 1976) reported a temperature o f 100°F a t 500 feet, and a gradient o f 5.5OC/lOO feet.

Based on t h i s gradient and a temperature o f 100°F a t 500 f e e t a temperature o f 145OF should be obtainable by reworking t h e w e l l t o a depth of 950 feet.

This well i s 1500 f e e t northwest o f a w e l l a t Mazama School. The Mazama w e l l has a bottom temperature o f 142OF a t 972 feet. The l a v a rock forma- t i o n begins a t 950 f e e t a t Mazama and may be s l i g h t l y shallower a t the SThooler property. For design we have estimated a 950 f o o t w e l l w i l l y i e l d 127 gpm o f 14OoF geothermal water. An i n j e c t i o n w e l l , also 950 f e e t deep, i s thought t o be required t o r e t u r n t h e used geothermal water t o the same aquifer. The formation appears t o lack t h e necessary permeability f o r i n j e c t i o n a t shallower l e v e i s .

casing i s proposed t o a 500 f o o t depth. The remaining 450 f e e t i s an 8"

base w i t h a 6" casing.

For both wells, a 10" base w i t h 8"

Faci 1 i t i e s

A s i m p l i f i e d diagram o f the proposed f a c i l i t i e s i s shown on Figure 1.

Geothermal water a t 14OoF i s delivered by a t u r b i v e pump developing 325 f e e t o f head a t 127 gallons per minute. The geothermal water flows through an i n s u l a t e d pipe t o a p l a t e heat exchanger. Design duty f o r t h e exchanger i s 1.85 MM BTU/HR, removing 3OoF from the geothermal water. The water then flows through a network o f uninsulated buried pipe t h a t heats the walks and driveways. The cooled geothermal water a r r i v e s a t t h e i n j e c t i o n w e l l w i t h 30 p s i g o f i n j e c t i o n pressure. The i n j e c t i o n w e l l i s located a t the northwest corner o f t h e property t o provide the maximum separation between the wells.

Flow through the closed secondary loop i s provided by a c i r c u l a t i n g pump t h a t d e l i v e r s 118 gpm a t 355 f e e t o f head. Loop water a r r i v e s a t t h e p l a t e heat exchanger a t 98.5oF and leaves a t 130OF. Outside l i n e s are b u r i e d w i t h supply l i n e s i n s u l a t e d and r e t u r n l i n e s uninsulated.

water i s provided by a 130OF s l i p stream o f f the heated loop water. Ave,rage demand i s 3.65 gallons per minute.

The apartments are heated

by

i n d i v i d u a l h o t water fan c o i l units.

Requirements f o r t h e u n i t s are:

Domestic h o t Peak demand has n o t been d e t e r m i n e z

Basis :

Water i n 1 3OoF

Water o u t 1 OO°F

A i r i n 650F

A l r o t

A i r fyow

&%FM

c o i l : F i n height 12"

F i n l e n g t h 15'l

Face area 1.25 square f e e t

Tubes per row 7

.

Number o f rows 3

12 Fins per inch

Duty 34,130 BTU/HR

Number feeds 1

Number passes 21

518" Copper tubes, aluminum f i n s

Water l e a v i n g the f i n c o i l s i s returned t o a suction drum f o r the c i r - c u l a t i n g pump.

d e t a i l e d a system f o r c o n t r o l l i n g f l o w and temperature i s provided f o r i n the estimate. P i p i n g costs were based on s t e e l pipe i n sizes from 2 1/2"

t o 3/4".

and a wrapped cover over insulated pipe i n the building.

should consider the p o t e n t i a l problem o f e x t e r i o r corrosion on buried s t e e l pipe if unprotected.

Makeup domestic water a l s o enters the drum. Though n o t

I n s u l a t i o n i s 2" urethane foam, a PVC j a c k e t on buried pipe, Final design

Cost Analysis

The c o s t analysis used a savings o f e l e c t r i c a l costs assuming 95% occupancy and i n f l a t e d these savings a t 7% which i s assumed t o be t h e economic

i n f l a t i o n rate.

Percentage depletion a1 lowances were assessed, these savings are as f o l 1 ows :

1980 22%

1981 20%

1982 18%

1983 16%

1984 through 1998 15%

Depreciation was based on s t r a i g h t - l i n e depreciation, a 20 year l i f e , and a 10% salvage value.

E l e c t r i c a l pumping costs were assumed t o i n f l a t e a t 9.5% annually through 1986 and 8.58% thereafter.

Operation and maintenance costs i n f l a t e a t 7% annually and t h e property taxes and insurance are projected t o increase a t 1% per year.

The company i s assumed t o be i n a 48% effective t a x bracket f o r federal income t a x purposes.

CAPITAL COST SUMMARY

School e r Apartments

K1

amath Fa1 1 s

,

Oregon 50 Apartments

TABLE

1

Geothermal w e l l , rework e x i s t i n g w e l l t o 950'

10" Bore x 8'' case x 500'

, ^8"

^{bore x 6"} case x 450'

I n j e c t i o n w e l l new w e l l 950' deep

10" Bore x 8" case x 500', 8" bore x 6" case x 450'

Geothermal and secondary p i p i n g system Turbine pump 127 gpm (3 325' head

Secondary c i r c u l a t i n g pum 125 GPM (3 355'

Pump/exchanger b u i l d i n g 12' x 15'

Fan c o i l heaters 50

-

34,130 BTU/HR u n i t s Miscellaneous e l e c t r i c a l & mechanical P1 a t e heat exchanger (geo

P

hermal /secondary)

Subtotal

-

Contingency I n s t a l l e d c o s t

C r e d i t f o r e l e c t r i c furnaces n o t i n s t a l l e d

C r e d i t f o r e l e c t r i c water heaters n o t i n s t a l l e d 50

-

^{10 KW} u n i t s

50-52 g a l l o n u n i t s

I - .

..

^. ..

$ 21,000

23,000

32,000 8,000 8,000 5,000 6,000 10,000 5,000 118,000

12,000

$1 30,000

18,000

9,000

$1

03,000

(1) Excludes any engineering o r contractors fees, b u i l d i n g permits o r licenses, o r cost e s c a l a t i o n

L

-

INCOME SUMMARY

School e r Apartments K1 amath Fa1 1

s ,

Oregon

50 Apartments

TABLE 2

Annual power savings (1 00% occupancy) E l i m i n a t i o n o f e l e c t r i c furnaces

Basis: 50

-

^{10 KW} u n i t s , 2295 heating hours per year

50 x 10 x 2295

E l i m i n a t i o n of e l i m i n a t i o n o f e l e c t r i c water heaters Basis: 50

-

52 g a l l o n water heaters

2 changes per day, 80OF r i s e i n water temperature

52 x 80 x 8.31 x 2 x 30

- -

⁶⁰⁸

^KWH

341 3 Apartment x Month

608 x 50 x 12 =

1,148,000

-

^KWH

Year

364,800

Total Power Saving 1,512,800 KWH

Year

Value o f power savings @ $.0260/KWH

1,512,800 x .0260 = $39 ,333Iyear

Monthly premium r e n t a l t o generate income equivalent t o value o f power savings 8 100% occupancy

39,333 = $65 p e r month 50 x 12 x 1.0

I n i t i a l t o t a l income f o r economic c a l c u l a t i o n s 8 95% occupancy

39,333 x .95 = $37,366.35

*

OPERATING COST SUMMARY

Schooler Apartments K1 amath Fa1 1 s

,

Oregon

50 Apartments

TABLE 3

Operating Cost:

Maintenance

-

P i p i n g @ 1/2% of i n s t a l l e d c o s t 32,000 x .005 =

Pumps

,

exchangers

,

fan c o i l s

,

exchanger, b u i l d i n g @ 3%

54,000 x .03 = Wells

-

N e g l i g i b l e T o t a l maintenance

Taxes and insurance 8 2 1/2% o f i n s t a l l e d cost (except w e l l s ) (130,000

-

^{44,000) x .025)}

E l e c t r i c a l pumping costs (3 $.0260/KWH

‘Tu rb i ne pump 36,000 KWH/Y R

C i r c u l a t i n g pump 45,000

Total 81,000 KWH/YR

I n i t i a l annual o p e r a t i n g c o s t

Depreciation

-

20 year s t r a i g h t - l i n e w i t h 10% salvage value

103,000 x .9 20

$/YR 160

1,620 0 1,780

2,150

2,106

$ 6,036/year

$ 4,635/year

1 2

3

4 5 6 7

8

9

10

1 1 12

13

14 15 16 17

18

19 20

,I

'.

39,982 42,781 45,775 48.,980 52,408 56,077 60,002 64,202 68,697 73,505 78,651 84,156 90,047 96,350 103,095 110,312 1 1 8,033 126,296 135,136 144,596

cost o f Year E l ec.

-

Depletion c i a t i o n ^Depre-

8,796 8,556 8,240 7,837 7,861 8,412 9,000 9,630 10,304 11,026 11,798 12,623 13,507 14,453 15,464 16,547 17,705 18,944 20,270 21,689

4,635 4,635 4,635 4,635 4,635 4,635 4,635 4,635 4,635 4,635 4,635 4,635 4,635 4,635 4,635 4,635 4,635 4,635 4,635 4,635

TABLE

4

COST ANALYSIS

Operation &

E l e c t r i c a l Maintenance Insurance Costs f o r Costs f o r & Property Geothermal Geothermal Taxes for Sys tem System Geothermal

2,306 2,525 2,765 3,028 3,315 3,630 3,975 4,316 4,687 5,089 5,525 5,999 6,514 7,073 7,680 8,339 9,054 9,831 10,675 11,591

1,905 2,038 2,181 2,333 2,497 2,671 2,858 3,058 3,272 3,502 3,747 4,009 4,290 4,590 4,911 5,255

5,623

6,016 6,437 6,888

2,172 2,193 2,215 2,237 2,260 2,282 2,305 2,328 2,351 2,375 2,399 2,423 2,447 2,471 2,496 2,521 2,546 2,572 2,597 2,623

Net Income Before Taxes

13,308 22,833 25,740 28,910 31,840 34,446 37,228 40,234 43,447 46,879 50,547 54,467 58,654 63,129 67,909 73,015 78,470 84,297 90,521 97,170

Federal Income

Tax

0 0 9,103 13,877 15,283 16,534 17,870 19,312 20,854 22,502 24,263 26,144 28,154 30,302 32,596 35,047 37,666 40,463 43,450 46,641

A f t e r N e t .

Tax A f t e r Depre.& Cash Taxes Depletion

Flow 13,308 13,431 26,739 22,833 13,191 36,024 16,637 12,875 29,511 15,033 12,472 27,505 16,557 12,496 29,053 17,912 13,047 30,959 19,359 13,635 32,994 20,922 14,265 35,187 22,592 14,939 37,532 24,377 15,661 40,038 26,285 16,433 42,717 28,323 17,258 45,581 30,500 18,142 48,652 32,827 19,088 51,914 35,312 20,099 55,412 37,968 21,182 59,150 40,804 22,340 63,144 43,835 23,579 67,414 47,071 24,905 71,944 50,528 26,324 76,853

Income Plus

TOTAL

31 % Net Presen

Value

20,41 20,99, 13,12

9,33*

7,53 6,12 4,98 4,05 3,30 2,691 2,19 1,78 1,45 1,18 96 78 64 52 42 34

102,86

7

3 C

2 a-

0 t

-8

I