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Passive (and Active) Cooling

Passive cooling techniques (solar chimneys, thermal mass, ventilation, roof ponds, ...).And, efficient active cooling techniques

Passive Cooling:

Passive Cooling Guides and Tools

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Shading Reflective Roofs (and Walls) Cooling Towers & Solar Chimneys Earth Tubes Reflectors Tips

Active Cooling:

Efficient Active Cooling - Ventilation Efficient Active Cooling - Evaporative Efficient Active Cooling - More ways

Questions? Report Broken Links ...

Passive Cooling Basics

The Energy Source Builder newsletter

http://www.oikos.com/esb/51/passivecooling.html

A very good article that provides a simplemethod to allow you to determine whichpassive cooling techniques are bestfor your climate.

This article is based on the book "Sun,Wind and Light" (see below).

Be Cool -- Natural Systems to Beat the Heat

Preethi Burkholder with Claire Anderson

How to get articles from Home Power ...

Home Power magazine article in issue108 (Aug/Sept 2005)

Very good article on simple techniques toprevent heat gain and to provide passivecooling.

It includes a method to determine which cooling techniques will workbest for your climate.

Design a Home That Keeps You Cool, Naturally,William Hoffman, Fine Homebuilding August 2004

How to get articles from Fine Homebuilding ...

A home that illustrates how anumber of simple coolingtechniques that were combinedin this house to avoid the needfor air conditioning in this southFlorida climate.

Passive Cooling -- Part 1 and 2Cliff Mossberg

Home Power magazine article,issue 82 and 83

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How to get articles from Home Power ...

Article on passive design coolingtechniques for hot humid climateswith examples. Many techniquescovered.

Lakeland, Florida -- Side by Side Test,Florida Solar Energy Center

Comparison of energy of a home designed with manyenergy efficiency features to a same size conventionalconstruction home.

http://www.fsec.ucf.edu

This is a very detailed and carefullydone study of two houses of the samesize in Lakeland Florida. One housewas built conventionally, and the otherwas equipped with a wide array offeatures to reduce energyconsumption, including: reflective roof,internal duct system, thermal massinside insulation, high efficiency and

properly sized AC, well designed overhangs, and optimalwindows. The measured energy consumption was 70% less on the house withlow energy use features. A solar PV system offset and additional22%, bringing the net energy use to near zero.The reports provide quite a bit of detail on the saving achieved byeach energy efficient design feature.

Passive Solar Cooled House in Tropical Areas

http://kotaronishiki.com/

This is a fascinatinghouse in LeytePhilippines that ispassively cooled usinga number of uniquemethods including adouble roof, a strategyfor shading south and

north walls in low latitudes using the roof, and double walls on theeast and west for shading.

The house also uses day to night temperature differences andbasement cooled air as part of the cooling strategy.

This house is definitely worth taking a look at if you live in a lowlatitude hot climate.

Arizona Solar Center -- Passive Cooling

www.azsolarcenter.com/technology/pas-3.html

A good overview of passive coolingstrategies.

Passive Cooling for Your North Carolina Home

North Carolina Solar Center

NC Passive Cooling Guide (pdf)

Good guide to passive cooling housesin the SE humid and warm climates.

From the NC Solar Center

Landscaping for Energy Efficiency

South Carolina Energy Office

Landscaping for Energy Efficiency (pdf)

Booklet on landscaping for energyefficiency. "Carefully positioned treescan save up to 25% of household'senergy consumption".

Several other energy saving "briefs" alsoavailable here.

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Window Overhang Sizing Tool

Sustainable By Design Solar Tools

http://www.susdesign.com/tools.php

Properly sized overhangs onsouth windows keep you cool inthe summer and collect sun inthe winter.

Designing Shading Overhangs with Google SketchUp

http://www.sketchup.com/

Be sure to pick a location near you, or enter yourlatitude/longitude -- otherwise, sun motions and shadowswill not be correct.

SketchUp is a free 3D drawingtool from Google. In addition tobe exceptionally easy to use as ageneral purpose drawing tool, itoffers a shadows made by a builtin sun. You can easily draw awall with a window and overhang,and play the sun over it forvarious times of day and times ofyear. It could also be used to layout

your whole house (with trees and sunspaces), and see how the sunplays over it.VERY easy to learn.

Sun, Wind and Light -- Architectural Design Strategies,2nd Edition

G. Z. Brown and Mark DeKay

Details on a large number of specificdesign strategies for making effectiveuse of the sun and wind, and naturallighting. It includes quantitativeanalysis techniques for eachstrategy. Intended for architects, butquite readable. Covers commercialbuildings as well as residences.

2001 400 pages

Radiant Barriers,SouthFace.org -- Energy Fact Sheet

www.southface.org Radiant Barrier Fact Sheet

A short but good Fact Sheet on radiantbarriers from SouthFace.org.

Climate Consultant,UCLA Energy Design Tools

http://www.energy-design-tools.aud.ucla.edu/

Note: the psychrometric charts that this tool produces havean overlay indicating which type of cooling techniques willwork well in your climate. A really nice tool.

Climate Consultant is one of the UCLAEnergy Design Tools.It provides a variety of ways to visualizeweather for a specific location. Weatherdata files are available for hundreds oflocations. This is a brand new version, andis very easy to use. "It graphically displays climate data in either metric

or imperial units in dozens of ways useful to architects including monthly barcharts, timetable charts, and psychrometric charts, sun shading charts, and sundial charts."

One of the most interesting charts is the Psychrometric chart withoverlays that show the design strategies (e.g. passive solar,evaporative cooling, ..) will work for the location in question.

Radiant Barrier Pilot Project,Florida Solar Energy Center,D. Parker, J. Sherwin, and M. Anello

http://www.fsec.ucf.edu

An FSEC evaluation of the energysaving for radiant barriers. Ninehouses were monitored for attictemperatures and AC energy usebefore and after installing a radiantbarrier.Bottom line was an about 10%reduction in AC energy costs, and a

somewhat improved comfort level.

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Shading Structures

Window (and house) Shading

How to keep cooler, save money, and be green all at thesame time

Window Shading Techniques

Gary

As much as half the heat gain to your house cancome from unshaded windows. The sunny dayheat gain from a hundred square feet of east orwest facing window is the equivalent of runningyour furnace for several hours.This is my 2 cents worth on several effective and(mostly) inexpensive ways to shade yourwindows and cut down on house overheating,high AC bills, and greenhouse gas emissions.

Sun Screens

http://sunbloxinc.com/

An article on this product:www.energyrefuge.com/archives/solar_screens.htm

The screen material from Phifer:http://www.phifer.com/ExtSunControl.aspx

And another -- there are lots of them:http://www.ezsnapdirect.com/

Exterior window shades -- search for shades:A similar screening from Real goods

This seems like a pretty good idea forreducing summer heat gain on windows. Theshades block up to 90% of sunlight, andmount in vinyl frames (like bug screens). Itlooks like they would work on a wide varietyof windows, including ones that would bedifficult to handle with other shadingtechniques. They do the shading on theoutside, where its most effect.

It seems like a DIY version could be worked out. The Phifer SunTexmaterial is said to be available at some home centers. Framescould probably be made from the same material that home centerssell for making insect screens.

Exterior Roll Up See Through Shades

Details...

These are exterior shades that roll downto to provide filtered shade, but still allowa view out.

We have these, and like them.

Details...

My Neighbor's Outstanding Trellis

All the details ...

My neighbor has a terrifictrellis with vines shadingstructure. It makes for a greatshady place to sit on hot sunnysummer days. In the winterwith the leaves gone, itprovides filtered sun andsome solar gain to the windowarea behind.And, it provides beautiful fall

color.All the details ...

Alnet DIY Rollup Shade Cloth Shades

www.shade-cloth-diy.com/patio-enclosures/patio-enclosures.shtml

Plans for a simple rollup shade fromshade cloth.

Trellis Cooling

Pictures of the trellis and other passive cooling featureshere:

ECO house in Rio de Janero uses analuminum trellis to support plants thatwill shade the house wall from from

sun.

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www.inhabitat.com/2005/12/23/ecohouse-brazil/

Living Wall System

http://www.eltlivingwalls.com

In addition to all the "green"benefits that these living wallsprovide, it seems like they could bevery useful for reducing heat gainfrom walls that get a lot of sun.

Lots of example photos and some"hot to" information at this website.

Trellis Shading

DoItYourSelf.com Trellis Projects

Some sample projects/pictures that use anexternal trellis for shading. This approach workswell on East and West facing windows whereoverhangs are not effective.

Shading Structures from 2007 Solar Decathlon

A little more on the German entry:www.inhabitat.com/...

Quite a few Solar Decathlon pictures from Inhabitat:www.flickr.com/photos/inhabitat/1636531291/

German entry in the 2007 Solar Decathlon had a niceporch/shading structure. Note the roof of porch is PV modules. Note that this would even work on east and west exposures.

And, this nice overhang on theUrbana-Champaign entry.

Click pictures to enlarge.

Pictures from Inhabitat

Unique Bamboo Shading Structure Shades Full House

http://inhabitat.com/...

A home in France built to PassiveHouse Standards uses a veryunique shading structure thatshades the full south wall of thehouse with movable bamboo

shutters.

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Some Trellis or Plant Screen Ideas ... These are some shading trellis or plant screen ideas excerptedfrom a discussion on the HomeEnergySolutions Yahoo discussiongroup

Thanks to the folks at HomeEnergySolutions for the good ideas!!

The Green Shutter

www.inhabitat.com/2006/03/08/green-shutter/

A pretty neat design for a operable shutterwith plants for sun control.

Schiavello Vertical Garden

From Inhabitat:http://www.inhabitat.com ...

This design seems as though it might work wellfor blocking unwanted solar gain on windows(particularly on difficult to shade east and westfacing windows).For this purpose, it would best be installedoutside the window on the ground or on abalcony.Judging from the comments, it might be good tothink about some type of watering system.

Alnet DIY Awning Plans

www.shade-cloth-diy.com/awnings/awnings.shtml

www.shade-cloth-diy.com/awnings/retractable-awnings.shtml

Plans for a simple wood framed, shade clothawning to provide window shade and reduceheat gain.

Retractable version

Alnet DIY Pergola Plans

www.shade-cloth-diy.com/pergolas/pergolas.shtml

Plans for a simple wood framed, shade clothpergola from Alnet.

Alnet DIY Trellis

www.shade-cloth-diy.com/garden-designs/garden-designs.shtml

Plans for a simple wood framed, shade clothtrellis fro Alnet

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Elegant Shade Structure

Popular Mechanics

www.popularmechanics.com

Plans for a very elegant shade structure. This could be used as a standalone shadestructure or adapted to shade a housewindow.

Very detailed plans.

Windsor Shade shelter

California Redwood Association

www.calredwood.org/ref/pdf/shelter.pdf

Detailed plans for a free standingshading structure.

Could be used for yard/deck shade, orto shade a window.

Rollup shade plans

From Charlie's Green Housewww.CharliesGreenhouse.com

The Plans (pdf)

Plans for a simple rollup shade fromCharlie's Greenhouse in Seattle.

Solar Deck Canopy -- How Well Does It Let Light ThroughDuring Winter?Amy Heidner, PE, 2012

This is a very interesting paperdemonstrating the use of PV panels aspart of a shade canopy that providesshade for living space that wasoverheating and generates solarelectricity as well.

The aim of the project was to providesufficient shading to keep the living areabehind the canopy from overheating,while at the same time not providing somuch shade that the the deck and livingarea would be too dark.

The authors found that by selecting a PVmodule design that lets some light through and adding some glazedareas above and below the PV modules that they could get just theright light levels under the canopy.

Shade Sails ,,,

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Shade Sails (or Solar Sails)are fabric membranessupported by fixed anchors,and positioned to provideshade. They are laid out and tensioned in such a wayas to be very resistant towinds.

They can be used to shadedecks, porches, play areas, windows, ...They can be very nice looking indeed, and can handle somedifficult shading problems.

Example photos, and design information here ...

Reflective Roofs

Comparative Summer Attic Thermal Performance of SixRoof Constructions,Danny Parker and John Sherwin, Florida Solar Energy Center, 1998

The full paper ...

This is an excellent paper that comparesthe attic temperatures for 6 different roofconstructions.

Following the findings of this study can

have a major impact on your cooling

costs.

If you don't have time to read the full paper, here is my quicksummary of the findings...

Cool Metal Roofing

www.wbdg.org/resources/coolmetalroofing.php

Reflective metal roofing can keep yourhouse cooler and save on cooling bills.

Measured Cooling Energy Savings FromReflective Roofing Systems In Florida:Field And Laboratory Research Results,Parker, Barkaszi, Chandra, and BealFlorida Solar Energy Center

www.fsec.ucf.edu/en/publications/html/fsec-cr-1220-00/

Measured and Simulated Performance of ReflectiveRoofing Systems in Residential Buildings,Parker, Huang, Konopacki, Gartland, Sherwin, and Gu.

www.fsec.ucf.edu/en/publications/html/fsec-pf-331-98/

A sampling of commercial sources ...

Actual measurements of reduction incooling energy for 8 homes in Floridabefore and after coating the roof with areflective (white) coating.

Cooling energy savings averaged 20%just by going to a more reflective roof.

The papers cover both roofing materials that are reflective as wellas coatings that can be applied on existing roofs.

The paper on Roofing Material Reflectivity is good and surprising.

"CoolWall" Paint

http://www.texcote.com/coolwall.php

ORNL Report... (pdf)

The flip side of this is that if you live in a cold climate,painting your home with a dark shade will result in a savingin heating energy.

"CoolWall" paint reduces cooling costs byformulating the paint to be reflective in theIR, but any color you like in the visiblespectrum. In other words, you can get thesame sort of cooling benefit that comesfrom painting your house white withouthaving to have a white house.

While many of the "save energy with paint" schemes are scams,this one has been tested extensively by he ORNL (see links), anddoes result in a 4 to 21% reduction in cooling energy.It should not be used in cold climates in that the same highreflectance in the IR that reduces cooling energy use increasesheating energy use. For example, in Richmond VA, the reduction insummer cooling energy is more than offset by the increase in winterheating energy.In the ORNL testing, white paint outperforms the IR reflective coolwall colors -- so, white paint is good for hot climates.

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David's White Roof Experiment ... David painted his roof white tomeasure the amount of cooling that thereflective roof brought to his attic andliving area.

White roof paint experiment ...

From one of the comments on this David's roof:"...all houses in traditional villages on Greekislands have white roofs. And they use lime, justlike you."

Wolfgang's Cool White Roof...This is another roofmade hightly reflectiveusing hydrated lime tocoat an existing roof.

The coating is veryreflective, and while itdoes not last forever, itdoes last longer thanyou might think.

Wolfgang has kept track of attic temperature and AC use andreports significant savings.

Cooling Towers & Solar Chimneys

Ventilation Rates for Solar Chimneys

Energy and Buildings -- 32

www.ecaa.ntu.edu

Paper provides measured ventilationrates and room temperatures achievedby four solar chimney designs.

Passive Air Conditioning -- Low Energy CoolingTom Elliot

http://www.i4at.org/lib2/aircool.htm

Another writeup on evaporative coolingtowers with some design information.

How to Stay Cool in the Hot Desert (with less power)

Charles Van Meter

http://millennium-ark.net

A passive cooling tower that uses windand water evaporation for cooling. Noblowers -- only electric demand is asmall water pump.Some design rules, and several yearsoperating experience.

Reflectors

Reflector/Shades, Steve Baer, Zomeworks Corporation

Reflector Shades paper... pdf

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http://www.zomeworks.com/sunbender/ A good paper by Steve Baer reviewing theuse of seasonally moveable reflectors toincrease solar heat gain in the winter, andreduce unwanted heat gain in the summer.A nice mix of solar physics and practicalhow-to that Steve has gained in the buildingof many of these types of reflector systems

over the years.

Earth TubesEarth tubes are tubes buried in the ground deep enough to take advantage of the more even year round temperature at depth. Air from outside the houseis run through the earth tubes to heat or cool it before it is introduced into the house. In the summer, the earth is cooler that the outside air temperatureand the air will be cooled as it goes through the tubes, and the opposite in the winter. This is a simple, energy efficient means of pre-heating or pre-cooling air, but there are a number of things to consider -- so do your homework carefully.

Wikipedia Article on Earth Tube Cooling...Pretty good introductory article on earth tube cooling fromWikipedia.

Performance of Single Pass Earth-Tube Heat Exchanger:An Experimental Study,Girja Sharan, Ratan Jadhav

Data from an Earth Tube experiment:Earth Tubes2003-01-07GirjaSharan.pdf

An interesting paper withsome actual data on a realearth tube -- this might behelpful in designing yourearth tube.The data includestemperatures along thetube, airflows, fan power,

and COP.

Passive Annual Heat Storage, John Hait, 1983

http://www.earthshelters.com/

This book by John Hait is mostly about hisPassive Annual Heat Storage home design,but it does have a section on earth tubes andhow they are used on his houses.

An interesting all around book.

The Natural Home Building on Earthtubing:

http://www.thenaturalhome.com/earthtube.htm

Describes the way in which earthtubes are used in their house design.

They also describe an earth tubesystem using water rather than air inthe pipes: http://mb-soft.com/solar/alternwa.htm

its hard for me to tell whether they have actually built one of these ornot.

Earth Tube Cooling -- Leopold Legacy Center

Aldo Leopold Earth Tubes Paper

A large commercial application usingearth tube cooling.

Some design numbers provided.

Analysis, Design, and Prelimnary Testing of Solar chimneyfor Residential Air-Conditioning Applications,Gang Wang, Bing Chen, Mingsheng Liu, Joerg Henkel,

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University of Nebraska, Lincoln

This paper looks at the feasibilityof using a solar chimney to driveflow through an earth tube.Both analysis and testing areprovided.

REHAU Air - Ground Heat Exchangers

http://export.rehau.com/ ...

This company makes components for earth tubeheating and cooling systems.

The downloadable pdf provides some usefulinformation for designing earth tube systems.

(thanks to Charles for finding this)

Ground Temperatures as a Function of Location, Season,and DepthVirginia Tech

EarthTemperatures.htm

This material from the Virginia Tech websiteon Geothermal Heat Pumps has some goodmaterial on the variation in groundtemperature with depth below the surface,area of the country, and season.

Earth Tube Design Notes...

Gary

These are just some thoughts on earth tube design based onnothing more than reading the articles above.

Efficient Active Cooling -- Ventilation

In some climates, fan forced ventilation and a 24 hour cooling strategy to reduce heat gain during the day, and make use of coolnight air can be very effective.

Whole House Fan for Cooling

Whole House Fan pdf (240K)

For relatively dry climates with coolnights, whole house fans are veryeffective in reducing or eliminatingthe need for refrigerated AC. I havehad a whole house fan in my last twohouses, and would not be withoutone!

Whole House Fans Tech Sheet (pdf)

PG&E

Another good guide on using andinstalling a whole house fan.

Big Fans in the Window As Whole House Fan,

Renewable Energy for the Poor Man -- Cheap AC

This is a nice and inexpensive wayto get the equivalent of a wholehouse fan by using two large fansmounted in a window.This is cheaper, you don't have tocut a hole in the ceiling (and seal itup for winter), and you can just takeit out for the winter. Flow rates appear to be close that

that of a whole house fan.

Energy Star Ceiling Fans

www.energystar.gov

Getting the Most from Your Fan,Chris Calwell and Noah Horowitz

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Home Energy

Choosing and Installing a Ceiling Fan,Fernando Pages Ruiz,Fine Home Building Magazine(very good how-to on installing ceiling fans)

Ceiling fans are an efficient cooling method forsome climates and conditions, especiallywhen the use of a ceiling fan allows less useof AC.

Energy Star ceiling fans use half as muchenergy as typical non Energy Star fans.

Note the directory of approved fans, and the attention to making anylight that might be included with the fan an efficient one.

If you have several ceiling fans in your house, using energy efficientfans could save you as much as 1000 KWH a year, so its worthfinding good ones and sizing them for the space.

Some thoughts on choosing an efficient ceiling fan ...

Ceiling fans with aerodynamically designed blades

http://www.fanworks.com/vari-cyclone.htm

Ceiling fans with "Gossamer Wind"technology blades move about 40% moreair for the same power use.Models are available that operate at 12

or 24V, and can be operated direct PV

or battery.

FSEC paper: Performance and Applications of Gossamer Wind™Solar Powered Ceiling Fans

Choosing and Installing a Ceiling Fan,Fernando Pages Ruiz, Fine Homebuilding, Nov 2001issue 142

How to get articles from Fine Homebuilding ..

A Fine Homebuilding article onchoosing and installing a ceilingfan. Lots of detail on mechanicalinstallation for both newconstruction and remodel, anddetail on how to wire the fan.

Solar Attic Vent Fan

http://www.arttec.net/Solar/5-21-06/May21-06.html

Guy Marsden describes how to install a solarpowered attic vent fan.

The fan lowers his attic temperature by abut20 to 30F, which reduces heat transferthrough the ceiling.

Adding attic insulation and sealing plumbingand wiring penetrations through the attic

ceiling are other ways to lower heat transfer from the attic to theliving space.

Cooling Without AC

Details...

This is the way we cool our house in SWMontana without using conventional AC.

The strategy involves avoiding daytimeheat gains, using cool night air for thermalmass cooling, and evaporative cooling ona few occasions. No AC.

Our cooling bills are less than $3 per month! Details ...

Night Breeze Cooling System

http://www.davisenergy.com/...

Home Energy Magazine articleKicking the Air conditioner Habit (pdf)

This is sort of a highly sophisticatedversion of a whole house fan. It eliminatesor reduces the need for refrigerated airconditioning by using cool night air to pre-cool the house for the next hot day.

Fran's Use of Subterranean Air to Defeat the Evil AirConditioner

Fran shows how he used cool airfrom his basement to defeat the evil

air conditioner.

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The whole story...

A nice simple and effective systemand a well written story ...

Efficient Active Cooling -- Evaporative Cooling

In some climates, evaporative (Swamp) coolers can be very effective in both reducing energy bills and avoiding that crumby, air-conditioned space feeling.

Evaporative Cooling

EERE Evaporative Cooler Basics...

http://www.consumerenergycenter.org/...

CEC - picking/sizing evaporative coolers...

Evaporative coolers can be veryeffective and energy efficient in hotclimates that do not have highhumidity. The newer indirect modelscan even be used in climates withsomewhat higher humidity.The constant circulation of air avoidsthe stuffy feel of conventionally airconditioned spaces.

Mike the Las Vegas Handyman Cuts Annual Power Bill By60% With A Swamp Cooler

http://www.pro-handyman.com/...

This is a good article that covers: 1) thekind of savings that can result from a"swamp" cooler, 2) how to use a swampcooler optimally, and 3) some good tipson installing and maintaining one.Mike is in Las Vegas and reports a 60%on his annual electric bill since using a

swamp cooler for most of the cooling season over that past coupleyears.

Cooling Without AC

Details...

This is the way we cool our house in SWMontana without using conventional AC.

The strategy involves avoiding daytimeheat gains, using cool night air for thermal

mass cooling, and evaporative cooling ona few occasions. No AC.

Our cooling bills are less than $3 per month! Details ...

Innovative Design Eliminates Cooling Equipment

Energy Source Builder #36, December 1994.

http://www.oikos.com/esb/36/Inno_Des.html

Article describes a house in Davis, CA(103F summer design temperature) withno refrigerated air conditioning system. The system uses night time ventilationand thermal mass to provide cooling. Anevaporative cooler is operated at night tocool thermal mass.

New Evaporative Cooling Systems -- An EmergingSolution for Homes in Hot Dry Climates with ModestCooling Loads

Southwest Energy Efficiency Project

Evap Cooler Report (pdf)

Evaporative Cooler Assessment from ToolBase:http://www.toolbase.org

Two stage evaporative coolers:www.homeenergy.org ...

Good and detailed report on a newgeneration of evaporative coolersthat are more efficient, use lesswater, and require lessmaintenance.

These cooler in a relatively dryclimate can save 90% compared tocompressor driven conventional air

conditioning!

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PV Powered Evaporative Coolers

http://www.southwest-solar.com/

Some notes on a DIY one:www.voltscommissar.net/competitive_edge.htm

These evaporative coolers use low HP 12Vfans that can be powered by PV arrays.

Night Sky Roof Water Spray Cooling system

www.ornl.gov/sci/eere/international/Website/WhiteCap.htm

Whitecap roof cooling system report...

ORNL gov report

While these papers seem to be aimed primarily atcommercial applications, residential applications may wellbe workable, simple, and energy efficient.Most beneficial for dry climates.

"This innovation spray-cools water onthe roof at night and applies thecooled water to reduce subsequentcooling loads. On clear nights, thesky is much colder than outdoor air,contributing to high water coolingrates through a combination ofevaporation and sky radiation.Overnight, NightSky systems can

typically cool a large storage volume (preferably two gallons persquarefoot of roof surface) to a final temperature as much as 12 degreesbelow the minimum night air temperature."

Seems like a very promising way to reduce the energy cost ofcooling. The 5600 sqft prototype described in the first link achievedan EER of 149.

Some Information on Designing and Building EvaporativePad Cooling System

Ohio State University Fact Sheet

http://ohioline.osu.edu/aex-fact/0127.html

Information for designing and making yourown evaporative pad cooling systems.

I have seen systems of this type ingreenhouses for cooling.

Plans for Evaporative Coolers

Info on several evaporative cooler schemes forgreenhouseswww.gothicarchgreenhouses.com/...

The Paper (pdf)

www.ag.ndsu.nodak.edu/abeng/plans/6208.pdf

Detailed plans for making evaporativecoolers. Intended for greenhouses, but may beadaptable to other situations.

Small, DIY, portable, solar powered evaporative coolers

http://robotfun.wordpress.com/2011/12/21/swampcooler/

This is a pretty slick homemade evaporativecooler. This one was made for camping, butit could be used in a variety of situations.

It can be solar powered, so its also good forsaving energy and for power outages.

Christin provides nice detailed instructionsas well as links to other small and larger DIYevaporative coolers.(Thanks to BeGreen at the Hearth.com forum forsuggesting this)

Turbo Kool Evaporative Cooler

http://www.turbokool.com/

Install Manual (pdf)

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http://www.builditsolar.com/Projects/Cooling/passive_cooling.htm 16/18

This is a small 12 VDC evaporativecooler that is intended for RVs,construction equipment, ... but mightwork well in any small space. The fan draws 4 amps, and thecompany says it will run directly off a

60 watt solar panel.

Efficient Active Cooling -- More Ways (radiation cooling, hydronic, roof sprinklers, misters, ...)

Increasing AC Efficiency Using Evaporative Cooling ofCondenser Coil

Full details...

Chad uses evaporative cooling toreduce the temperature of the air thatcools the condenser coil on his airconditioner.

The AC efficiency is significantlyaffected by the condenser cooling airtemperature, so this change bothincreases the AC capacity and alsoreduces energy use. This evaporativecooling scheme does not leavemineral deposits on the condenser

coil.

Chad's scheme uses all off the shelf parts and is fully documented ina 16 page pdf....

Theoretical Evaluation of the NightCool NocturnalRadiation Cooling ConceptDanny S. ParkerFlorida Solar Energy Center (FSEC)

New report on the NightCool performance in test buildings:Experimental Evaluation of the NightCool NocturnalRadiation Cooling Concept: Performance Assessment inScale Test Buildings,Danny S. Parker, John R. SherwinFlorida Solar Energy Center (FSEC)

Daily performance of the test buildings,http://infomonitors.com/ntc/

Note: I would tend to NightCool in the Experimental area,

so, if you go after this, bear in mind you may suffer the

"being a pioneer" learning curve. Please let us knowhow it comes out.

This is a simple, building integrated,cooling scheme that uses nighttime radiation cooling from a metal roof tocool air in the attic space. Attic air isthen circulated into the living area toprovide cooling.A simulation model is used to predict

performance in various climates -- the scheme works very well in dryareas, and fairly well even in very difficult moist-warm climates (e.g.Florida).One of the attractive features of this system is that the roof is veryconventional -- no massive ponds or moving insulation.There is the potential in some climates to use the same metalroofing/attic system for space heating in colder weather.The new test report shows the results for two 10' by 16' structuresthat were built to compare NightCool performance to conventionalAC in Florida. Very interesting and promising results.Tests of a a simple dehumidification system using desiccants arenow underway.

Florida Zero Energy Test House

Florida Solar Energy Center

The Report (pdf)

A home constructed in a verydifficult cooling climate (centralFlorida) to see if a combinationof passive cooling techniques toreduce heat gain, high efficiencyAC, efficient appliances, and a

fairly large PV rig could produce near zero net energy use. Thehome was largely successful in meeting these goals.Net energy use was only about 18% of a control house built tocurrent codes. Pretty good detail on how much energy each feature saved.My 2 cents would be that the passive cooling, high efficiency AC,and efficient appliances contributed 67% the of the savings, whileadding little to the cost of the house. The 4KW PV rig contributedthe other 33% of the savings, and probably cost about $40,000.

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Night Air Thermal Mass Cooling Using Water Barrels

All the details on water barrel space cooling...

This is a scheme that I amexperimenting with to cool myshop. It basically blows coolnight time air over a collectionof 50 gallon barrels filled withwater to store "coolth" in thewater.

The method looks like it mightprovide cooling with a COP of

42 (SEER 140) or more!

While I am using the scheme in my shop, it could be used to coolany interior space. The basic question is: does it make sense to

use a fan forced flow of cool night air over thermal mass to store"coolth" for later use in daytime cooling? Details...

Hydronic Cooling

Energy Source Builder, Issue 53

http://www.oikos.com/esb/53/hydroniccool.html

An article from the Energy Source BuilderNewsletter on using hydronic heating systemsfor cooling, including radiant floor systems.

Roof Sprinkler Cooling System,John

Full Details ...

A paper on sizing commercial roof spray coolingsystems...

Roof sprinkler system lowers roof temperatureand cooling bills by keeping the roof coolerthrough water evaporation.

Added a description of another similar system3/6/07

Brown Machine Works -- Cool Rain system

http://fp1.antelecom.net/bromac/7.html

This is a small business that offers a roofsprinkling system to cool attic areas. Theyalso sell parts to people who want to buildtheir own system.

They have a detailed installation manual thatshould be helpful to those building a system.

Clay Tile Roof Cooling in the Central Valley...

This is a brief description from Davidon how roof sprinkers are used inCalifornia's Central Valley for cooling...

Simple Control System for Roof Sprinklers Thanks to Curt for sending in this note:"In this small 1000 sq ft slab and block beach home, a well pump provided waterto a washing machine water valve that was actuated with a temperature switchfrom an attic exhaust fan which operated both the fan and the valve. Connectedto the water valve was a soaker hose like the ones used to water a garden,mounted on the roof's peak. There was no other cooling system in the house."

Sounds like a nice simple way to do the control system for roofsprinkler.

Mist Cooling

DripWorks.com sells a misting kit thatprovides mist cooling for about 25 lineal feet

(3 misters). Said to be easy to hook up.

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www.dripworksusa.com/...

Mist cooling can be very effective andcomfortable if done well.

I've ordered the kit and will report on how itdoes.

It looks like water usage is about 3/4 gallonper hour per mister outlet.

Mist Cooling For Large Outdoor Areas

A very simple mist cooler for large outdoorareas. Intended for cows, but I don't thinkthey will mind if you use their idea.

Using Your Lawn Sprinkling Water to Cool the House

Rick uses a water to air heatexchanger to extract some "coolth"from the water he is using to waterthe lawn.

Its basically free cooling.

All the details on Rick's coolingsetup...

Cooling Tips

Sleep Genie -- A sleep Compartment with AC

http://www.sunfrost.com/sleep_genie.html

From Sunfrost

You might combine the Sleep Genie with the built in bedconcept shown in Mother Earth Magazine: Construct aCozy Build-in Bed, MaxwellFinding Mother Earth News articles...

An interesting concept to provide acomfortable, air-conditioned environment in alimited space for sleeping comfort.

It saves the energy cost ofneedlessly air-conditioning a largespace when your are onlyoccupying a small space.

The same idea could be used for the heatingseason with a small heater in the bed cubby.

Water bed cooling Randy suggests that in hot climatessleeping directly on the water bed bladderwill be cooler.Remove all the coverings except for asheet or two, and let the water conductheat away from your body.The temperature of the water in thebladder will be the average of the last few

days, and cooler than body temperature.After more experience, Randy adds that during the cooler season,you want more insulation (e.g. a blanket) between you and the waterbladder to keep it from getting to chilly. Its a mater of adjusting theamount of insulation between you and the thermal mass.

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