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Chapter 1.1

BALNEOLOGICAL USEOF THERMAL WATERS

John W. LundGeoHeat Center, Klamath Falls (OR), U.S.A.

E-mail: lundj@oit.edu

PART 1: “TAKING THE WATERS’ -INTRODUCTION TO BALNEOLOGY

Background

People have used geothermal waterand mineral waters for bathing and theirhealth for many thousand of years. Bal-neology, the practice of using natural min-eral water for the treatment and cure ofdisease, also has a long history. Based onarcheological finds in Asia, mineral waterhas been used for bathing since the BronzeAge, about 5000 years ago. Many hotsprings have been used in connection withreligious rites in Egypt and by the Jews ofthe Middle East. The Greeks, Turks andRomans were famous for their spa devel-opment and use from Persia to England.The word “spa” traces its origin to a townnear Liège in southern Belgium near theGerman border. Here a spring of iron-bearing water was used by an iron master in1326 to cure his ailments. He founded ahealth resort at the spring called Espa(meaning fountain in the Walloon lan-guage). Espa became so popular that theword know in English as spa became thecommon designation for similar health

resorts around the world (Lund, 1996). Great spas have a long history, often

stretching back to Roman times. Bath inEngland, for instance, was originallyknown as Aquae Sulis, Baden-Baden inGermany as Aquae Aureliae, and Aix-lesBains in France as Aquae Allobrogum(Rockel, 1986).

Today, especially in Europe and Japan,the use of medically supervised spas haslong been accepted. They are used forboth treatment and preventive therapy.The former Soviet Union had 3500 spasand some 5000 reconditioning centers alladministered and run by the state. In theformer Czechoslovakia, there are 52 min-eral water health spas and more than 1900mineral springs, which every year about220,000 citizens are granted free spatreatment for three weeks, paid by the na-tional health insurance program. Themore famous ones are Karlbad in the pre-sent Czech Republic and Piestany in Slo-vakia. Many of these spas are being pri-vatized today, and are dependent on in-come from visits by persons from outsidethe country. In Rotorua, New Zealand, theQueen Elizabeth Hospital used variousmineral waters and hot springs muds to

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help soldiers from the WWII Pacific warsrecuperate from battle injuries. In Japanthere are over 1500 spas that are used byover 100 million visitors every years.Some of these international uses have beendocumented by Hotta and Ishiguaro (un-dated) Lund (1992 and 1996) in “Storiesform a Heated Earth” (1999), and theGeo-Heat Center Quarterly Bullet-in(1993).

The Indians of the Americas conside-red hot springs as sacred places and be-lieved in the healing powers of the heatand mineral waters. Montezuma, the greatAztec leader, spent time at a spa, AquaHedionda, to recuperate from his strenuousduties; which was later developed into afashionable spa by the Spaniards (Salgado-Pareja, 1988). Every major hot spring inthe U.S. has some record of use by the In-dians, some for over 10,000 years. Thesesprings were also known as neutral ground,to which warriors could travel and restunmolested by other tribes. Here theywould recuperate from battle. Today, thereare approximately 210 spas in the USAwith 4.5 million persons attending a spa in1997. Details on the U.S. use of mineralwaters and hot springs can be found in Part2: Balneological Use of Thermal Watersin the USA in this publications.

Improving your health and your ap-pearance, and getting away from stressesto refresh and revitalize your body andyour mind are the main reasons why peo-ple go to spas and why spas are becomingan increasingly important part of Ameri-can life. The 7-day miracle, as some referto a week’s spa vacation, provides youwith a necessary interlude to change yourpace of life and your way of being, to loseweight, shape up, reduce stress, gain confi-dence, reassess your goals, recharge yourvitality, learn new exercise and nutritionbehaviors, reward yourself with time outfor yourself--and have a good time, a care-free holiday (Van Itallie and Hadley, 1988)

What is a spa?

The word “spa” is also used as a Latinabbreviation for: S = salud, P = per, A =aqua, or “Health through Water.” In

Germany, they refer to the “Kur”, whichdoes not mean just a cure, but instead is aseries of treatments over time includingbaths, taking (drinking) water, massage,exercise, mud baths, etc.

For the sophisticated European ofthe nineteenth century, a spa was muchmore than just a health resort. The fa-mous spas of France, Germany and Britainwere elegant social and cultural centers.Most who took the cure [“kur”] did not doso primarily for medical reasons, but to seeand be seen by high society (Rockel,1986).

Other definitions include ( De Vier-

ville, 1998):“The spa is the social aspect of using

water therapeutically.”“The spa is a natural space and place

with a perspective on time.”“A spa is a space with a purpose,

through a plan, by a purpose, for a periodof time.”

Spas today can have many formsand emphasize certain treatments. Sarnoff, (1989) classified American spas asfollows: Intensive fitness spas - where fitnessbuffs can trim and tone “to the max” inminimum time. Rejuvenation spas - where you cantake advantage of the latest beauty treat-ments for a younger-looking you. Weight-loss spas - where you can va-cation and shed those unwanted pounds atthe same time. Athletic camps - where excellentsports programs and exercise classes can behad at a very affordable price. Mineral springs or “magic mud” re-sorts - where health-giving waters and theoldest, most aristocratic spa traditionsawait you. New Age retreats - where you can re-new your psychic and spiritual self as wellas physical well-being. Gustatory hideaways - where you canenjoy and learn about the best in healthful,nonfattening, gourmet fare.

Thus, in summary the purpose of a spais to provide (DeVierville, 1998): Water (therapeutic through heat and

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minerals, including muds) Movement (exercise, massage and fit-ness) Herbal (medical benefits) Dietary (proper food and drink) Life style pattern.

And a spa, to be successful, must have(DeVierville, 1998): Hygiene (cleanliness) Service A unique attractions, such as scenery,special water, special mud, special cure,special food, unique location, unique facil-ity, etc.

Planning and Developing Spa (De-Vierville, 1998):

A spa plan must have the following fora successful development: Vision Mission Goals Objectives Strategies (how to accomplish theplan)

The categories and dimensions that arepart of a spa and should, for the most, beincorporated into its development are: Natural, environmental, ecological Medical, psychological, therapeutic Scientific, technical, research Economical, financial, managerial Planning, architectural, building Social, fashionable, gastronomical Artful, historical, literal Spiritual, mystical, religious

Finally, the items necessary for a spaare: 1. Water 2. Food or nutrition 3. Exercise or movement 4. Massage or body work 5. Mind-body - physiological 6. Natural therapeutic agents (muds) 7. Environment - area, climate 8. Cultural aspects 9. Management and staff (marketing)10. Life style patterns or rhythms (time).

Water and Muds

A spa originates at a location mainly

due to the water from a spring or well.The water, with certain mineral constitu-ents and often warm gives the spa meaningfrom one or more of the following pointsof view (DeVierville, 1998):

Religious, mythical, symbolic Social, political, economic Aesthetic, artistic, literary Philosophical, scientific, technological and medical.

Associated with most spas are the usedof muds (peloids) which either are found atthe site or are imported from special loca-tions. As an example, at Piestany in Slo-vakia, there is a special laboratory thattest muds or clays for their mineral con-tent and their therapeutic benefits. Themuds are stored in tanks and “cured” formaximum benefit.

The three classification of muds are: Pure mineral (fango, mud) - neutral Mainly mineral (sea mud or liman) -

alkaline Mainly vegetable peloid (moor, peat) -

acid

The skin effects of mud are: Increase the body temperature Lowering of blood pressure Influence on mineral metabolism andblood chemistry

Even though hot mud packs have beentouted for many aliments, the recom-mended uses for local treatment are (De-Vierville, 1998): 1. Chronic arthritis 2. Fibrositis 3. Neuritis, sciatic syndrome 4. After treatment of fractures 5. Sport and industrial injuries.

Typical Spa Design

There are many types of designs forspas, depending upon the local culture, theunique character of the location, and whatthe developer is trying to achieve in termsof atmosphere, service and type of clien-tele. Two basic types, with an emphasison the use of geothermal water will be pre-sented here.

The first (Fig. 1) is one originallyproposed for Hawaii (Woodruff and Taka-

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hashi, 1990). This design which includesliving quarters surrounding the variousbathing and soaking pool, lends itself tofeature native plants and material in thelandscaping and construction. Also, foodand drink can be provided, along withsmall shops and a fitness room for a healthand fitness program. The enclosed poolarea would provide privacy, but also alloweasy access to and from the living area.

The second design (Figure 2) wasalso proposed for Hawaii (Woodruff andTakahashi, 1999). This design emphasizesprivate, semi-private and public bathingand soaking facilities. This is also typicalof the design for the Polynesian Pools inRotorua, New Zealand. This design doesnot include living quarters, but these couldbe added at a separate location and couldbe individual cottages. The semi-privateand private pools could then be used by asingle family and rented on a hourly basis.This would also be appropriate in cultureswere bathing in public is less accepted.

Both of the above designs could beuncovered, completely enclosed or eachindividual pool covered with a temporaryroof for use in inclement weather. Un-covered pools are extremely popular inthe evening under a star-lite sky.

Figure. 1. General scheme of a moderngeothermal spa located in California(Woodruff and Takahashi, 1990).

Figure 2. Design for a geothermal spaoffering private, semi-private,and publicbathing facilities (Woodruff and Takaha-

shi, 1990).

REFERENCES

DeVierville, J. P. (1998). Director, Alamo PlazaSpa at the Menger Hotel, San Antonio, TX, personal communication, (also on the Boardof Directors of the International Spa Asso-ciation Foundation).

Geo-Heat Center Quarterly Bulletin (1993).Nine articles on hot springs, spas and balne-ology in the U.S., Vol. 14, No.4, Geo-HeatCenter, Klamath Falls, OR, 32 p.

Hotta, A and Y. Ishiguaro (undated). A Guideto Japanese Hot Springs. Kodansha Interna-tional, Tokyo, Japan.

Lund, J. W. (1996). Balneological Use ofThermal and Mineral Waters in the U.S.A.,Geothermics, Vol. 25, No. 1, Elsevier Sci-ence, Ltd., Great Britain, pp. 103-147.

Lund. J. W. (1992). “Geothermal Spas inCzechoslovakia.” Transactions , Vol. 16,Geothermal Resources Council, Davis, CA,pp. 3-7.

Rockel, I. (1986). Taking the Waters - EarlySpas in New Zealand, Government PrintingOffice Publishing, Wellington, 195 p.

Salgado-Pareja, J. S. (1988). Hydrothermal Ac-tivity in Mexico: Its Utilization for Genera-

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tion and Balneology.” Geo-Heat CenterQuarterly Bulletin, Vol. 11, No. 2, KlamathFalls, OR, pp. 4-7.

Sarnoff, P. M. (1989). The Ultimate Spa Book,Warner Books, New York, 276 p.

Stories from a Heated Earth - Our GeothermalHeritage (1999). Edited by R. Cataldi, S.F. Hodgson and J. W. Lund (34 papers onearly uses of geothermal energy), Geother-mal Resources Council, Davis, CA, 568 p.

Van Itallie, T. B. and L. Hadley (1988). TheBest Spas, Per-ennial Library, Harper &Row, Publishers, New York, 431 p.

Woodruff, J. L. and P. K Takahashi (1990).Geothermal Spas: A New Business Oppor-tunity in Hawaii, Transactions, GeothermalResources Council, Vol. 14, Part 1., Davis,CA, pp. 819-824.

PART 2: BALNEOLOGICAL USE OFTHERMAL WATER IN THE USA

Introduction

In the United States, the use of naturalsprings, especially geothermal ones, havegone through three stages of development:(1) use by Indians as a sacred place, (2)development by the early European set-tlers to emulate the spas of Europe, and(3) finally, as a place of relaxation andfitness.

The Indians of the Americas consid-ered hot springs as a sacred place of Wa-kan Tanka (“Great Mystery” or Great Sa-credum” in the Lakota language) and thus,were great believers in the miraculoushealing powers of the heat and mineralwaters. Every major hot springs in theU.S. has some record of use by the Indians.They were also known as neutral ground,where warriors could travel to and restunmolested by other tribes. Here theywould recuperate from battle. In manycases, they jealously guarded the spring andkept its existence a secret from the arriv-ing Europeans for as long as possible. Bat-tles were fought between Indians and set-tlers to preserve these rights. The earlySpanish explorers such as Ponce de Leonand Hernando DeSoto were looking for the“Fountain of Youth,” which may havebeen an exaggerated story of the healingproperties of one of the hot springs.

The early European settlers in the1700 and 1800s, found and used thesenatural hot springs, and later realizingtheir commercial value, developed manyinto spas after the tradition in Europe.Many individual developments were suc-cessful such as at Saratoga Springs, NewYork; White Sulphur Springs, West Vir-ginia; Hot Springs, Virginia; Warm Springs,Georgia and Hot Springs, Arkansas. How-ever, the U.S. did not have the govern-ment, trade unions, social security and anational health insurance program to sup-port these developments. Thus, in spiteof the benefits of spa therapy that hadbeen proven successful in Europe and else-where in the world, the U.S. lagged behindin the development of these mineralsprings even though some were acquired bystate and the federal government. By the1940s, the interest in spas languished, andmost of the majestic resorts went into de-cline and closed.

The health and fitness industry hasrecently been stimulated by increasingconsumer interest worldwide, resulting inhigh growth in revenues and profits. Theindustry in the U.S. exceeded $35 billion inrevenue in 1984. Health spas and resorts,representing a major part of the healthand fitness industry, have grown in popu-larity and offer high investment potential.Revenues from spas in the U.S. presentlyare estimated at $10 billion annually. Thenumber of spa-goers is projected to growfrom 31% of the adult population in 1987to 45% in 1997. The most traditionaltype of health spa is the geothermal spa,featuring baths and pools of natural hotmineral waters.

This recent interest in hot springssoaking and physical fitness has renewedthe development of spas in the UnitedStates. This natural way of healing andthe “back to nature” movement has inmany ways rejected formalized spa medicaltreatment developed in Europe. In fact,the average person in the United Statesknows little of spa therapy and its advan-tages as many of the medical claims havebeen outlawed in the U.S., and the naturalwaters have required chlorination or otherchemical treatment. The main reason

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people in the U.S. go to geothermal spasare to improve their health and appear-ance, to get away from stresses, and torefresh and revitalize their body and mind.Unlike European spas where medical curesof specific ailments are more important,U.S. spas give more importance to exer-cise, reducing stress, lifting depression andloosing weight. A recent interest is thedevelopment of “health conservancies” topreserve natural areas for health and fit-ness activities.

The use of mineral and geothermalwaters has developed along three lines inthis country: (1) the more plush hotsprings resorts with hotel-type servicesand accommodations, (2) commercialplunges or spring pools and soaking tubswith perhaps a snack bar or camping facili-ties, and (3) the primitive undevelopedsprings without any services (Sunset Maga-zine, September 1983). Many resorts andnatural hot springs have an informal dresscode while soaking, including nude bath-ing. They have satisfied health depart-ment requirement for chemical treatmentby allowing the water to continuously flowthrough without treatment. Several publi-cations have been written on the subject,documenting these facilities and their use.In the case of the resorts, two books areavailable: “The Best Spas” by Van Itallieand Hadley, 1988, and “The Ultimate SpaBook” by Sarnoff, 1989. Plunges and hotsprings are well documented in severalpublications, such as: “Great Hot Springsof the West” by Kaysing, 1990; “Hot

Springs and Hot Pools of the Northwestand Eastern States” by Loam and Gersch,1992, and “The Hiker’s Guide to HotSprings in the Pacific Northwest” by Lit-ton, 1990. Similar publications are alsoavailable for other parts of the country.

Location and Chracteristicsof the U.S. Spas

There are over 115 major geothermalspas in the USA, and many more smallerones along with thousands of hot springs(1,800 reported by NOAA, 1980). Themajority of these are located in the vol-canic regions of the western states; but,several famous ones still exist in the east.The major spas are estimated to have an

annual energy use of 1.531 x 1012 kJ, oran equivalent of 340 thousands barrels ofoil (BOE). Details of some of these U.S.spas are presented in Geo-Heat CenterQuarterly Bulletin, Vol. 14, No. 4, March1993, and in Lund, 1996. Thermal watersin geothermal spas vary greatly in compo-sition from place to place. Table 1 showssome analyses of the major constituents ofwater from thermal springs and wells inseveral locations. “N/a” indicate that novalue were available and does not neces-sarily mean that components were absent.Concentrations are in mg/L. The compo-sition of average sea water is included forcomparison (Woodruff & Takahashi,1990).

Table 1. Composition of Waters from Several Locations (mg/L)

(1) (2) (3) (4) (5) (6)

Na 4.0 326.2 520 690.0 290.0 10500K 1.5 89.6 82 15.0 0.08 380Mg 4.8 121.6 38 0.2 0.08 1270Ca 45.0 624.0 150 210.0 34.00 400Cl 1.8 217.6 n/a 1300.0 106.00 19000SO4 8.0 n/a 420 170.0 491.00 2650

SiO2 42.0 24.0 58 96.0 n/a n/a

HCO3 165.0 n/a n/a 17.0 n/a 140

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(1) Hot Springs, Arkansas (2) Thermopolis, Wyoming (3) Indian Springs, Colorado(4) Belkap Springs, Oregon (5) Desert Hot Springs, California (6) Average sea water

Interest in spas in the U.S. was notentirely lacking after the turn of the cen-tury, as both the federal and state govern-ments became owners and managers ofseveral important ones. Five examplesfollow (Fig. 1)(Lund, 1996).

Saratoga Springs, New York, located250 km north of New York City, had ap-proximately 18 springs and hot wells dis-

charging 13oC carbonated mineral wateralong a fault. The Mohawk and IroquoisIndian tribes frequented the springs duringhunting trips in the area. The first writtenreport of the springs by European settlerswas in the early 1600s (Swanner, 1988).Since this time, the springs have been usedfor drinking and bathing, to cure every-thing from skin disorders to digestiveproblems. The water and carbon dioxidehas also been bottled and sold as a com-mercial product. Because of use and de-cline in flow in the springs in the early1900s, the state of New York formedSaratoga Spa State Park, and now managesthe geothermal activity including the only

spouting geyser east of the MississippiRiver. Several of the older bathhouses,Lincoln and Roosevelt, have been restoredproviding mineral baths, hot packs andmassages. Two commercially bottled wa-ter are available: Saratoga Mineral Waterand Excelsior Spring Water. The presentSaratoga Spa Park has 10 springs withseven other springs located in the sur-rounding areas of the city.

Warm Springs, Georgia is another fa-mous mineral springs in the U.S. Thesprings were used by Indians from as faraway as New York, as they were on a ma-jor trail system. The trails later becamemilitary and post roads, with a tavern builtin the early 1800s. A number of resortswere built in the area, including the veryvictorian Meriwether Inn. It is knowchiefly for the treatment of polio fromthe early 1920s to the 1960s. It was pro-moted by President Franklin Delano Roo-sevelt, who had polio and established the“Little White House” on the premises in1932. The Georgia Warm Springs Founda-

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tion, who managed the springs, dedicateditself to the conquest of polio. It providedtreatment in various pools supplied bywarm springs flowing around 58 L/s at

31oC. With the advent of polio vaccinesin the 1950s and 60s, use of the facilitydeclined. Today, the Roosevelt WarmSprings Institute for Rehabilitation of thestate of Georgia provides medical rehabili-tation and therapy for a broad range ofdisabilities. The Institute also uses the wa-ter for bathing, heating and cooling, as-sisted by water-to-air heat pumps.

Hot Springs, Arkansas was one of themost popular commercial spas areas in theU.S., created to imitate the developmentof great spas of Europe. This natural geo-thermal resource consisted of about 47springs producing a total of 4 million litersof 60oC water per day. It is estimatedthat these hot springs have been used byhumans for at least 10,000 years. The“Valley of the Vapors” was an honoredand sacred place to the Indians. This wasalso neutral ground, where warriors of alltribes could rest and bath here in peace--arefuge from battle. Legend reports thatHernando DeSoto, an early American ex-plorer, visited the site in 1541. Thesprings were developed into a rustic bath-ing and resort area in the early 1800s. Itbecame so popular with the early Euro-pean settlers, that it was made into a fed-eral reservation in 1832. By 1878, over50,000 people visited the springs annually.In 1921, it came under the jurisdiction ofthe newly formed National Park Serviceand was renamed Hot Springs NationalPark. People flocked to this new nationalpark with its large fancy bathhouses alongBathhouse Row. Until 1949, each bath-house needed to have its own evapora-tion tower in order to cool the incominghot mineral water to below 43oC, themaximum generally tolerated by the hu-man skin. In that year, the Park Serviceinstalled air-cooled radiators and tap-watercooled heat exchangers to supply cooledwater to the system. Now the bathhousesreceived two supplies of water: “hot” at62oC and “cool” at 32oC. Of the original47 springs, only two are presently avail-

able for public viewing. Even though ac-tivity has declined over the recent years, afull range of options are still available: tuband pool baths, showers, steam cabinets,hot and cold packs, whirlpool, massage, oralcohol rub. Today, the Park leases anumber of bathhouses and owns almost2000 hectars of land.Thermopolis, Wyoming is located at themouth of the Wind River Canyon, Ap-proximately 150 km southeast of Yellow-stone National Park. The major geother-mal attraction in the area is the HotSprings State Park with the 120 L/s BigHorn Spring. Nearby is the Fountain ofYouth resort using natural mineral waterfrom the historic Sacajawea Well flowingat the rate of 60 L/s. At least eight hotsprings in the area have created large ter-races along the river. These terraces arecomposed chiefly of colorful lime andgypsum layers known as travertine. Thesprings, claimed to be the large mineralhot springs in the world, flow at a tem-perature of between 22 and 56oC with atotal dissolved solids of 2400 mg/L. Theearly history of the springs include use byIndians; however in 1896, a treaty wassigned between the Shoshone and ArapahoIndians and the federal government whichgave the public use of the hot springs.The management of the springs was laterturned over to the state of Wyomingforming Hot Springs State Park. TodayHot Springs State Park consists of littleover 420 hectars of irrigated lawn and de-veloped area within the 26-square kmpark, providing geothermal bathing in theState Bathhouse, and free water to sixother facilities. Among the facilities pro-vided hot water is a Pioneer Center forretired state residents and the GottscheRehabilitation Center specializing in help-ing stroke victims, closed head and spinalinjuries, bed sores, cellulating problems,and burn victims.

Calistoga, California area was origi-nally settled by the Pomos and MayacmasIndians for at least 4000 years. Theseearly people came from miles around touse the natural hot springs, fumaroles, andheated muds to soothe aches and pains.

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They also built sweat houses and used thelocal cinnabar for red war paint. To them,this was the “beautiful land” and “the ovenplace.” In the early 1800s, the Spanishexplorers visited the area looking for apossible mission site. They referred to thissite as “Aqua Caliente.” Sammuel Brannan,in the 1850s, envisioned a resort and spasimilar to Saratoga Hot Springs--and thus,the name from a combination of Califor-nia and Saratoga (Archuleta, 1977). Hespent an estimated half a million dollarsdeveloping the “resort,” with his HotSprings Hotel opening in 1862. Aroundthe turn of the century, over 30 resortsexisted in the surrounding area, includingbathhouses, mineral springs, and resorthotels. By 1930, many of these resortshad closed due to financial hardship, firesand lack of maintenance. About 15 yearsago, Calistoga again became a “boom-town” with six major spas and resorts inoperation. All of these resorts have theirgeothermal water supplied from shallowwells around 60-m deep with temperaturefrom 77 to 93oC. The water for the poolsand baths is cooled to 27 to 40oC, andsome have mud baths using the local vol-canic ash and peat moss. Calistoga also hasa mineral water industry and is adjacent tothe Napa Valley wine industry.

Conclusions

Geothermal water has been used exten-sively for the hot pools and baths, but notfor heating or cooling the structures atthese spas. Space heating was attemptedin the past at many resorts, however, withmixed-to-poor results. Pipes would cor-rode or plug with deposits and require fre-quent repairs, replacement and cleaning.The expense was high and thus, “natural”space heating was usually replaced withconventional fossil fuel systems. Today,we at the Geo-Heat Center, and other geo-thermal experts, understand and solvethese problems on a routine basis. Thecost of installing the proper equipmentand safeguards are more than offset by thesavings in annual heating costs over fossilfuels. The Geo-Heat Center has a techni-cal assistance program funded by USDOE

to provide free engineering and economicdesign, and analysis of any use of a re-source for heating and cooling.

References

Archuleta, K. (1977). The Brannan Saga, EarlyDay Calistoga , Smith McKay Printing,Jose, CA.

Kaysing, Bill (1990). Great Hot Springs of theWest , Capra Press, Santa Barbara, CA.

Litton, Evie (1990). The Hiker’s Guide to HotSprings in the Pacific Northwest , FalcoPress, Helena, MT.

Loam, Jayson and Marjorie Gersch (1992). HotSprings and Hot Pools of the Northwest Aqua Thermal Access, Santa Cruz, CA.

Lund, John W. (1996). “Balneological Use ofThermal and Mineral Waters in the USA,”Geothermics , Vol. 25, No. 1, Pergamon,Elsevier Science, Ltd., Great Britain, pp.103-147.

Sarnott, P. M. (1989). The Ultimate Spa Book ,Travelers Bookshelf, Warner Books, NewYork, NY.

Sunset Magazine (September 1983). “HotSprings All Over the West,” Menlo Park,CA, p.74-79.

Swanner, Grace Maguire (1988). Saratoga -Queen of Spas , North Country Books, Inc.,Utica, NY.

Thermal Springs List for the United States(1980). Complied by George W. Berry,Paul Grim and Joy Ikelman, NOAA, Boul-der, CO.

Van Itallie, Theodore B. And Leila Hadley(1988). The Best Spas , Perennial Library,Harper & Row, New York, NY.

Woodruff, James L. and Patrick K. Takahashi(1993). “A New Business OpportunityinHawaii,” Geo-Heat Center Quarterly Bull e - tin , Vol. 14, No. 4, Klamath Falls, OR, pp.26-19.

PART 3: DESIGN CONSIDERATIONSFOR POOLS AND SPAS (NATATO-RIUMS)

Swimming Pools

According to ASHRAE (1999a), the

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desirable temperature for swimming poolsis 27oC, however, this will vary from cul-ture to culture by as much as 5oC. If thegeothermal water is higher in temperature,then some sort of mixing or cooling byaeration or in a holding pond is required tolower the temperature. If the geothermalwater is used directly in the pool, then aflow through process is necessary to re-place the “used” water on a regular basis.In many cases, the pool water must betreated with chlorine, thus it is more eco-nomical to use a closed loop for thetreated water and have the geothermal wa-ter provide heat through a heat exchanger.The water heating system in this case, isinstalled on the return line to the pool.Acceptable circulation rates vary from sixto eight hours for a complete change ofwater. Heat exchangers must be designedto resist the corrosive effects of the chlo-rine in the pool water and scaling or corro-sion from the geothermal water. This of-ten requires, in the case of plate heat ex-changers, using titanium plates.

Sizing of the system for temperatureand flow rates depends on four considera-tions (ASHRAE, 1999a), which are alsodiscussed in more detail in the chapter onAquaculture Design by Rafferty or in Raf-ferty (1998). These are:

Conduction through the pool walls,Convection from the pool surface,Radiation from the pool surface, andEvaporation from the pool surface.Of these, conduction is generally the

least significant unless the pool is aboveground or in contact with cold groundwa-ter. Convection losses depend on thetemperature difference between the poolwater and the surrounding air, and the windspeed. This is substantially reduced forindoor pools and ones with wind breaks.Radiation losses are greater at night, againespecially for outdoor pools, howeverduring the daytime there will be solar gainswhich may offset each other. A floatingpool cover can reduce both radiation andevaporation losses. Evaporation lossesconstitute the greatest heat loss frompools -- 50 to 60% in most cases(ASHRAE, 1999a). The rate at whichevaporation occurs is a function of air

velocity and pressure difference betweenthe pool water and the water vapor in theair (vapor pressure difference). As thetemperature of the pool water is increasedor the relative humidity of the air is de-creased, evaporation rate increases. Anenclosure can reduce this loss substantially,and a floating pool cover can practicallyeliminate the loss. Swimming and otherpool uses causing waves and splashing willincrease the surface area and thus theevaporation rate.

The required geothermal heatingoutput qt can be determined by the fol-

lowing two equations (ASHRAE, 1999a):

q1 = g cp V (tf - ti)/ [1]

where:q1 = pool heat-up rate, kJ/h

g = density of water = 1,000 kg/m3

cp = specific heat of water = 4.184

kJ/kg oCV = pool volume, m3

Tf = desired temperature (usually

27oC)ti = initial temperature of pool, oC

= pool heat-up time (usually 24 hours)

and:q2 = U A (tp - ta) [2]

where:q2 = heat loss from pool surface, kJ/h

U = surface heat transfer coefficient =214.4 kJ/(h m2 oC)

A = pool surface area, m2

tp = pool temperature, oC

ta = ambient temperature, oC

then:qt = q1 + q2 [3]

If there is no heat-up time, which istypical for geothermal pools, then equa-tion [1] will be zero and only equation [2]will apply. Heat loss equation [2] assume awind velocity of 5 to 8 km/h. For shel-tered pools, and average wind velocity ofless than 5 km/h can be assume, and thusthe second equation (q2) can be reduced to

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75%. For wind velocity of 8 km/h, multi-ply by 1.25; and for wind velocity of 16km/h, multiply by 2.0 (ASHRAE, 1999a).

Spas (Natatoriums)

Spas or natatoriums require year-round humidity levels between 40 and 60%for comfort, energy consumption, andbuilding protection (ASHRAE, 1999b).Any design must consider all of the fol-lowing variables: humidity control, venti-lation requirements for air quality (outdoorand exhaust air), air distribution, duct de-sign, pool water chemistry, and evapora-tion rates.

According to ASHRAE (1999b):

“Humans are very sensitive to relativehumidity. Fluctuations in relative hu-midity outside the 40 to 60% rangecan increase levels of bacteria, viruses,fungi and other factors that reduce airquality. For swimmers, 50 to 60%relative humidity is most comfortable.High relative humidity levels are de-structive to building components.Mold and mildew can attack wall,floor, and ceiling coverings; and con-densation can degrade many buildingmaterials. In the worst case, the roofcould collapse due to corrosion fromwater condensing on the structure.”

Heat loads for a spa include buildingheat gains and losses from outdoor air,lighting, walls, roof, and glass, with inter-national latent heat loads coming gener-ally from people and evaporation. Theevaporation loads are large compared toother factors and are dependent on the

pool characteristics such as the surfacearea of the pool, wet decks, water tem-perature and the activity level in the pool.

The evaporation rate (wp in kg/s) can

be estimated for pools of normal activitylevels, allowing for splashing and a limitedarea of wetted deck (Smith, et al., 1993)(ASHRAE, 1995).

wp = A (pw - pa)(0.089 +0.0782 V)/Y

[4]

where:A = area of pool surface, m2

pw = saturation vapor pressure taken

at surface water temperature, kPapa = saturation pressure at room air

dew point, kPaV = air velocity over water surface,

m/sY = latent heat required to change wa-

ter to vapor at surface water tem-perature, kJ/kg

For Y values of about 2330 kJ/kg andV value of 0.10 m/s, and multiplying by anactivity factor Fa to alter the estimate ofevaporation rate based on the level of ac-tivity supported, equation [4] can be re-duced to:

wp = 4.16 x 10-5 x A (pw - pa) Fa [5]

If pw and pa are given in bar absolute,

then equation [5] becomes:

wp = 4.16 x 10-3 x A (pw - pa) Fa [6]

And, if wp is given in kg/hr, then equa-

tion [6] becomes; wp = 15.0 x A (pw - pa) Fa [7]

Table 1. Common Values for pw

For pw: at 15oC water, pw = 0.0170 bar (1.70 kPa)

at 20oC water, pw = 0.0234 bar (2.34 kPa)

at 25oC water, pw = 0.0317 bar (3.17 kPa)

at 30oC water, pw = 0.0425 bar (4.25 kPa)

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at 35oC water, pw = 0.0563 bar (5.63 kPa)

at 40oC water, pw = 0.0738 bar (7.38 kPa)

For outdoor locations with a design drybulb air temperature below 0oC, pa can be

taken as 0.0061 bar (0.61 kPa). For in-door locations with a design from 40 and

60% humidity, the following values of pa

can be used:

Table 2. Common Values for pa

Temperature 40% relative 50% relative 60% relativeoC humidity humidity humidity

bar (kPa) bar (kPa) bar (kPa)

20 0.0094 (0.94) 0.0117 (1.17) 0.0140 (1.40)25 0.0127 (1.27) 0.0158 (1.58) 0.0190 (1.90)30 0.0170 (1.70) 0.0212 (2.12) 0.0255 (2.55)

The following activity factorsshould be applied to the area of specificfeatures, and not to the entire wetted area(ASHRAE, 1999b):

Type of Pool Typical Activity Factor(Fa)

Residential pool 0.5Condominium 0.65Therapy 0.65Hotel 0.65Public, schools 1.0Whirlpools, spas 1.0Wavepools, water slides 1.5 (minimum)

It is important to apply the correctactivity factor for the estimation of thewater evaporation rate, as for example,the difference in peak evaporation rates

between private pools (residential) andactive public pools of the same size maybe more than 100%.

ASHRAE (1999b) recommends op-erating temperatures and relative humidityconditions for design, and suggests thathigher operating temperatures are pre-ferred by the elderly. Air temperatures inpublic and institutional pools should be

maintained 1 to 2oC above the water tem-peratures (but not above the comfort

threshold of 30oC) to reduce the evapora-tion rate and avoid chill effects on swim-mers. The maximum water temperaturethat can be tolerated by the human body

(for short periods of time) is 43oC. Therecommendations are as follows:

Table 3. Typical Natatorium Design Conditions.

Air Water Temperature Temperature Relative

ºC Humidity % ºC

Type of pool:Recreational 24 to 29 24 to 29 50 to 60Therapeutic 27 to 29 29 to 35 50 to 60Competition 26 to 29 24 to 28 50 to 60Diving 27 to 29 27 to 32 50 to 60

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Whirlpool/spa 27 to 29 36 to 40 50 to 60

Relative humidities should not bemaintained below recommended levels be-cause of the evaporated cooling effect ona person emerging from the pool and be-cause of the increased rate of evaporationfrom the pool, which increases pool heat-ing requirements. Humidities higher thanrecommended encourage corrosion andcondensation problems as well as occupantdiscomfort. Air velocities should not ex-ceed 0.13 m/s at a point 2.4 m above thewalking deck of the pool (ASHRAE,1995).

Ventilation is important, especially ifchlorine is used to treat the pool water.Ventilation is also used to prevent tem-perature stratification in areas with highceilings. Since exhaust air will have chlo-ramine from the chlorine treatment andalso have high moisture contents, caremust be exercised to vent this air outsideand not into changing rooms, toilets andshowers. In addition, pool areas shouldhave a light negative pressure and auto-matic door closers to prevent the con-taminated air (laden with moisture andchloramine) from migrating into adjacentareas of the building. ASHRAE (1999b)states that most codes require a minimumof six air changes per hour, except wheremechanical cooling is used.

With mechanical cooling, the recom-mended rate is four to six air changes perhour for therapeutic pools.

Natatoriums can be a major energyburden on a facility, thus energy conserva-tion should be considered. This includesevaluating the primary heating and coolingsystems, fan motors, backup water heaters

(in the case of geothermal energy use) andpumps. Natatoriums with fixed outdoorair ventilation rates without dehumidifica-tion generally have seasonally fluctuatingspace temperature and humidity level.Since these systems usually cannot main-tain constant humidity conditions, theymay facilitate mold and mildew growth andpoor indoor air quality. In addition,varying activity level will also cause thehumidity level to vary and thus change thedemand on ventilation air.

REFERENCES

ASHRAE (1995). (American Society of Heat-ing, Refrigeration and Air-Conditioning En-gineers) 1995 ASHRAE Application Hand-book (SI), Chapter 4 - Natatoriums, At-lanta,GA, pp. 4.6 - 4.8.

ASHRAE (1999a). (American Society of Heat-ing, Refrigeration and Air-Conditioning En-gineers) 1999 HVAC Application Hand-book, Chapter 48 - General Applications:Swimming Pools/Health Clubs, Atlanta,GA, pp. 48.19 - 48.20

ASHRAE (1999b). (American Society of Heat-ing, Refrigeration and Air-Conditioning En-gineers) 1999 HVAC Application Hand-book, Chapter 4 - Comfort Applications:Natatoriums, Atlanta, GA, pp. 4.5 - 4.7.

Rafferty, K. (1998). Aquaculture, GeothermalDirect-Use Engineering and Design Guide-book, Chapter 15, Geo-Heat Center,Klamath Falls, OR, pp. 327-332.

Smith, C. C.; Jones, R. W. and G. O. G. Löf(1993). Energy Requirements and Poten-tialSavings for Heated Indoor SwimmingPools, ASHRAE Transactions 99(2), At-lanta, GA, pp. 864-74.