Difference between revisions of "Green Garage Solar Heating Design"
From Green Garage Detroit
Tom Brennan (Talk | contribs) (→Solar Heating System Overview) |
Tom Brennan (Talk | contribs) (→Radiant Floor) |
||
(28 intermediate revisions by 2 users not shown) | |||
Line 4: | Line 4: | ||
** Targeting meeting 90% of space heating load | ** Targeting meeting 90% of space heating load | ||
** Design Heating Season = Nov 15 - March 15 | ** Design Heating Season = Nov 15 - March 15 | ||
+ | *** (AR: This is pretty radical to get to Nov.15 with no heat, but reportedly this was well calculated with super insulation.) | ||
** Total Solar Heating Load = Space Heating Load + Domestic Hot Water | ** Total Solar Heating Load = Space Heating Load + Domestic Hot Water | ||
*** Space Heating Load = 22 million BTU per heating season; 184k BTU/day | *** Space Heating Load = 22 million BTU per heating season; 184k BTU/day | ||
+ | **** (AR: Again, by normal standards this is at least an order of magnitude low, but ...) | ||
*** Domestic Hot Water Load = 120 gals / day | *** Domestic Hot Water Load = 120 gals / day | ||
* See [[Green Garage - Current Design Assumptions]] | * See [[Green Garage - Current Design Assumptions]] | ||
Line 12: | Line 14: | ||
=== Solar Heating System Overview === | === Solar Heating System Overview === | ||
− | [[Image:Solar Heating Diagram V5.jpg|thumb|left| | + | [[Image:Solar Heating Diagram V5.jpg|thumb|left|600px|Green garage Solar Heating Schematic - V5]] |
<br style="clear:both;"/> | <br style="clear:both;"/> | ||
Line 21: | Line 23: | ||
** where Heat Output (Q-out) = Temp Rise x Volume Flow Rate x Specific Heat of Water | ** where Heat Output (Q-out) = Temp Rise x Volume Flow Rate x Specific Heat of Water | ||
* '''Basics Guidelines''' | * '''Basics Guidelines''' | ||
− | ** Solar thermal (liquid) panels are | + | ** Solar thermal (liquid) panels are 35% to 70% efficient ... 3 to 4 times that of PV panels |
** The efficiency varies greatly with delta T (Tin - Tout)the greater the difference the lower the efficiency | ** The efficiency varies greatly with delta T (Tin - Tout)the greater the difference the lower the efficiency | ||
* '''Solar Collectors''' | * '''Solar Collectors''' | ||
** Flat Panel vs. Evacuated Tube | ** Flat Panel vs. Evacuated Tube | ||
− | *** Choose: Flat panel because of lower cost (approx 1/3 the cost) and higher durability (twice the life)..performance usually better in the system vs. on the testing bench | + | *** Choose: Flat panel because of lower cost (approx 1/3 the cost) and higher durability (twice the life)..performance usually better in the system vs. on the testing bench |
** Manufacturer [[Image:SRCC Data - SunEarth Empire 4x10.png|thumb|100px|SRCC Data for SunEarth - Empire]] | ** Manufacturer [[Image:SRCC Data - SunEarth Empire 4x10.png|thumb|100px|SRCC Data for SunEarth - Empire]] | ||
*** [http://www.sunearthinc.com/ Sun Earth] | *** [http://www.sunearthinc.com/ Sun Earth] | ||
**** [http://www.sunearthinc.com/empire_series_flat_plate.htm Empire Flat Plate] and [http://www.sunearthinc.com/empire.pdf Spec] single glazed, copper, selective absorber |Intercept: 0.758, Slope: -0.727 | **** [http://www.sunearthinc.com/empire_series_flat_plate.htm Empire Flat Plate] and [http://www.sunearthinc.com/empire.pdf Spec] single glazed, copper, selective absorber |Intercept: 0.758, Slope: -0.727 | ||
**** [[Conversation with Bob at SunEarth on March 23, 2008]] | **** [[Conversation with Bob at SunEarth on March 23, 2008]] | ||
− | *** Others: [http://solarhotusa.com/index.html Solar Hot Panels] highly recommended, AET (STSS recommended), Solar Thermal System, Heliodyne large market share. [http://www.apricus.com/ Apricus] ... the evacuated version that Roman used. | + | *** Others: [http://solarhotusa.com/index.html Solar Hot Panels] highly recommended, AET (STSS recommended), Solar Thermal System, Heliodyne large market share. [http://www.apricus.com/ Apricus] ... the evacuated version that Roman used. [http://www.solene-usa.com/chromagen.php Solene Cromagen] - slightly better numbers and equally good pricing - just under $800 for a 4x10. |
* '''Preliminary Specifications''' | * '''Preliminary Specifications''' | ||
** Size: 4ft x 10ft | ** Size: 4ft x 10ft | ||
Line 36: | Line 38: | ||
** Positioning | ** Positioning | ||
*** On the annex building flat roof | *** On the annex building flat roof | ||
− | *** Vertical Angle: | + | *** Vertical Angle: 57-65 degrees per SRCC guide + Alan the panels should be (Latitude + 15 degrees) for winter heating driven systems |
− | *** Horizontal Angle: solar "true" south - determine at site...slightly west of magnetic south...estimated to be approx + | + | *** Horizontal Angle: solar "true" south - determine at site...slightly west of magnetic south...estimated to be approx + 5 degrees degrees for Detroit. +/- 15 degrees is ok. Site for [http://aa.usno.navy.mil/cgi-bin/aa_rstablew.pl sunrise/sunset data] |
*** Configuring | *** Configuring | ||
− | **** Portrait orientation | + | **** Portrait orientation (landscape is ok, but takes up more roof area) |
− | **** Parallel connection | + | **** Parallel connection (see diagram Alan's Solar Collector Design) |
− | **** One feeder pipe to two groups of five panels in parellel (i.e. five per manifold.) | + | **** One feeder pipe to two groups of five panels in parellel (i.e. five per manifold.) ** Thermal Capacity: |
− | ** Thermal Capacity: | + | |
*** 23 Million BTU per heating season (Nov15 - Mar 15) See [http://spreadsheets.google.com/ccc?key=poIdcdytevB8h_kYqyV41EA&hl=en GG Solar Thermal Workbook] | *** 23 Million BTU per heating season (Nov15 - Mar 15) See [http://spreadsheets.google.com/ccc?key=poIdcdytevB8h_kYqyV41EA&hl=en GG Solar Thermal Workbook] | ||
*** [http://www.sunearthinc.com/empire.pdf SunEarth Thermal Capacity] | *** [http://www.sunearthinc.com/empire.pdf SunEarth Thermal Capacity] | ||
Line 49: | Line 50: | ||
**** Partly Sunny: 560 BTU/sf Winter; BTU/sf Summer | **** Partly Sunny: 560 BTU/sf Winter; BTU/sf Summer | ||
**** Cloudy: 375 BTU/sf Winter; BTU/sf Summer | **** Cloudy: 375 BTU/sf Winter; BTU/sf Summer | ||
− | ** Flow Rate: | + | ** Flow Rate: .5g/m per collector: Total 5g/m. When you are dealing with a drainback with no heat exchanger on the solar loop side, .5 gpm/collector is adequate. A full 1 gpm wastes watts and adds wear and tear on the copper collector piping. |
− | ** Pressure: 160 psi | + | ** Pressure: 160 psi With drainback it is at atmospheric pressure +/-. With glycol, probably 15 to 25 psi. |
− | ** Temp: 15 - 25F delta T for T in vs. T out; | + | ** Temp: 15 - 25F delta T for T in vs. T out; Typically T in vs. T out is under 15 especially if you have more than about .6 gpm/collector. Max - can boil...control with the flow. Min: - above storage temp or radiant floor or indoor temp |
− | *** Overheating / Heat dump | + | *** Overheating / Heat dump If using a drainback approach, you have a little more leeway to handle occasional stagnations (no glycol to turn acidic), but some overheat protection is recommended - could be a good greenhouse/tarp-roll arrangement manually raised and lowered over part of the array - or a heat dump radiator of some sort. |
− | ***** | + | ***** Cover the panels. |
− | ***** | + | ***** Paint the panels with poster paint that washes off ...not sure about this one |
***** uses radiator coils with fans to dump heat | ***** uses radiator coils with fans to dump heat | ||
* '''Open Issues''' | * '''Open Issues''' | ||
− | ** Thermal capacity calcs...w/ domestic hot water | + | ** Drainback option that eliminates glycol? (AR: If possible, and I think it is, I would recommend drainback.) |
− | ** | + | ** Thermal capacity calcs...w/ domestic hot water...how many additional panels 2 vs. 3. |
+ | ** Insulation of panels? Not done. | ||
+ | ** Framing for mounting the panels? Minimize roof holes...new roof design? | ||
=== Thermal Storage=== | === Thermal Storage=== | ||
Line 77: | Line 80: | ||
*'''Preliminary Specifications''' | *'''Preliminary Specifications''' | ||
** Location of Storage | ** Location of Storage | ||
− | *** | + | *** Ground floor slab in addition bldg |
− | *** Create insulated room w/ R- | + | *** Create insulated room w/ R-25 walls + R-25 floor + R-25 ceiling |
** Thermal Architecture | ** Thermal Architecture | ||
*** All heat generators (i.e. solar and geothermal) connected to the storage | *** All heat generators (i.e. solar and geothermal) connected to the storage | ||
*** All heat consumers (i.e radiant heat and domestic hot water) can draw heat from storage via heat exchangers. | *** All heat consumers (i.e radiant heat and domestic hot water) can draw heat from storage via heat exchangers. | ||
** Size of storage | ** Size of storage | ||
− | *** Store | + | *** Store 2 million BTU to start (3,500 gallons) |
− | *** Number of tanks: 1 | + | *** Number of tanks: 1 - 3,500 gal |
*** Assume 1,500 gal | *** Assume 1,500 gal | ||
− | ** Size: | + | ** Size: 3,500 gal = 10 ft dia x 7ft tall |
− | + | ** Capacity: 470cf | |
− | ** Capacity: | + | |
** Thermal Capacity: | ** Thermal Capacity: | ||
− | *** Winter: | + | *** Winter: 3500 gals = 470cf = 2.3 mBTU: equivalent to approx 13 average winter days (almost two weeks) |
− | *** Summer: | + | *** Summer: TBD |
** Thermal Loss: R-19 around tank | ** Thermal Loss: R-19 around tank | ||
** Flow Rate: Max 15g/m ... geothermal connection | ** Flow Rate: Max 15g/m ... geothermal connection | ||
Line 98: | Line 100: | ||
** Temp: Max: 175F Min: above radiant floor or indoor temp | ** Temp: Max: 175F Min: above radiant floor or indoor temp | ||
* '''Open Issues''' | * '''Open Issues''' | ||
− | ** Number of tanks? | + | ** Number of tanks? Use 1 tank due to cost of heat exchangers |
− | ** | + | ** Do you need a small tank for the domestic hot water? Probably not....except for cooling season. |
− | ** What about using it for off-peak cooling storage for the geothermal? | + | ** What about using it for off-peak cooling storage for the geothermal? Haven't seen it done. |
=== Radiant Floor === | === Radiant Floor === | ||
Line 126: | Line 128: | ||
**** Reflective radiant barrier (could be foil on the XPS?) (mm) | **** Reflective radiant barrier (could be foil on the XPS?) (mm) | ||
**** Sleepers (1.5") with metal heat extenders | **** Sleepers (1.5") with metal heat extenders | ||
− | **** Plywood? Wood Flooring (1") | + | **** Plywood? Wood Flooring (1") '' |
**** All screwed together, run trenches | **** All screwed together, run trenches | ||
* '''Open Issues''' | * '''Open Issues''' | ||
− | ** Normal operating temps winter...summer? | + | ** Normal operating temps winter...summer? Winter = 90F max...summer = 68F min |
− | ** Can radiant floor be used for cooling? | + | ** Can radiant floor be used for cooling? Yes see ASHRAE report ... min 68 degrees |
− | ** Plex sizing in Michigan code? | + | ** Plex sizing in Michigan code? Appears we can use 3/4"...1/2 min |
=== Geothermal === | === Geothermal === | ||
Line 141: | Line 143: | ||
*'''Open Issues''' | *'''Open Issues''' | ||
** Geothermal - operating temps (min-max) | ** Geothermal - operating temps (min-max) | ||
+ | |||
+ | |||
=== Resources === | === Resources === | ||
+ | * [[Conversation with Alan Rushforth on April 2, 2008]] | ||
* Overall | * Overall | ||
** [http://www.thesolarguide.com/solar-thermal/radiant-heating.aspx Overall Concept] ... recommends thermal storage. | ** [http://www.thesolarguide.com/solar-thermal/radiant-heating.aspx Overall Concept] ... recommends thermal storage. |
Latest revision as of 13:30, 11 April 2009
return to Solar Heating Design
Contents
Demand Requirements
- Load Requirements / Assumptions
- Targeting meeting 90% of space heating load
- Design Heating Season = Nov 15 - March 15
- (AR: This is pretty radical to get to Nov.15 with no heat, but reportedly this was well calculated with super insulation.)
- Total Solar Heating Load = Space Heating Load + Domestic Hot Water
- Space Heating Load = 22 million BTU per heating season; 184k BTU/day
- (AR: Again, by normal standards this is at least an order of magnitude low, but ...)
- Domestic Hot Water Load = 120 gals / day
- Space Heating Load = 22 million BTU per heating season; 184k BTU/day
- See Green Garage - Current Design Assumptions
- See our GG Solar Thermal Workbook
Solar Heating System Overview
Solar Thermal Collectors
- Goal = highest Heat Output / Total Life-cycle Cost
- Should BTU generated per dollar invested...why not just buy little more of a slightly lower efficient panel that is much less expensive and get same total energy.
- where Heat Output (Q-out) = Temp Rise x Volume Flow Rate x Specific Heat of Water
- Basics Guidelines
- Solar thermal (liquid) panels are 35% to 70% efficient ... 3 to 4 times that of PV panels
- The efficiency varies greatly with delta T (Tin - Tout)the greater the difference the lower the efficiency
- Solar Collectors
- Flat Panel vs. Evacuated Tube
- Choose: Flat panel because of lower cost (approx 1/3 the cost) and higher durability (twice the life)..performance usually better in the system vs. on the testing bench
- Manufacturer
- Sun Earth
- Empire Flat Plate and Spec single glazed, copper, selective absorber |Intercept: 0.758, Slope: -0.727
- Conversation with Bob at SunEarth on March 23, 2008
- Others: Solar Hot Panels highly recommended, AET (STSS recommended), Solar Thermal System, Heliodyne large market share. Apricus ... the evacuated version that Roman used. Solene Cromagen - slightly better numbers and equally good pricing - just under $800 for a 4x10.
- Sun Earth
- Flat Panel vs. Evacuated Tube
- Preliminary Specifications
- Size: 4ft x 10ft
- Number: 10 = area 400sf
- Positioning
- On the annex building flat roof
- Vertical Angle: 57-65 degrees per SRCC guide + Alan the panels should be (Latitude + 15 degrees) for winter heating driven systems
- Horizontal Angle: solar "true" south - determine at site...slightly west of magnetic south...estimated to be approx + 5 degrees degrees for Detroit. +/- 15 degrees is ok. Site for sunrise/sunset data
- Configuring
- Portrait orientation (landscape is ok, but takes up more roof area)
- Parallel connection (see diagram Alan's Solar Collector Design)
- One feeder pipe to two groups of five panels in parellel (i.e. five per manifold.) ** Thermal Capacity:
- 23 Million BTU per heating season (Nov15 - Mar 15) See GG Solar Thermal Workbook
- SunEarth Thermal Capacity
- Assume
- Full Sun: 750 BTU/sf Winter; BTU/sf Summer
- Partly Sunny: 560 BTU/sf Winter; BTU/sf Summer
- Cloudy: 375 BTU/sf Winter; BTU/sf Summer
- Flow Rate: .5g/m per collector: Total 5g/m. When you are dealing with a drainback with no heat exchanger on the solar loop side, .5 gpm/collector is adequate. A full 1 gpm wastes watts and adds wear and tear on the copper collector piping.
- Pressure: 160 psi With drainback it is at atmospheric pressure +/-. With glycol, probably 15 to 25 psi.
- Temp: 15 - 25F delta T for T in vs. T out; Typically T in vs. T out is under 15 especially if you have more than about .6 gpm/collector. Max - can boil...control with the flow. Min: - above storage temp or radiant floor or indoor temp
- Overheating / Heat dump If using a drainback approach, you have a little more leeway to handle occasional stagnations (no glycol to turn acidic), but some overheat protection is recommended - could be a good greenhouse/tarp-roll arrangement manually raised and lowered over part of the array - or a heat dump radiator of some sort.
- Cover the panels.
- Paint the panels with poster paint that washes off ...not sure about this one
- uses radiator coils with fans to dump heat
- Overheating / Heat dump If using a drainback approach, you have a little more leeway to handle occasional stagnations (no glycol to turn acidic), but some overheat protection is recommended - could be a good greenhouse/tarp-roll arrangement manually raised and lowered over part of the array - or a heat dump radiator of some sort.
- Open Issues
- Drainback option that eliminates glycol? (AR: If possible, and I think it is, I would recommend drainback.)
- Thermal capacity calcs...w/ domestic hot water...how many additional panels 2 vs. 3.
- Insulation of panels? Not done.
- Framing for mounting the panels? Minimize roof holes...new roof design?
Thermal Storage
- Demand Requirements
- Space heating and domestic hot water. We're investigating cooling ideas.
- Goal is, practically speaking, 90% with a retro fit...no opportunity for below floor storage.
- 10 gallons ( or approx 1 cu ft) for every 1 sf of solar panel if you want to get to near 95% of heating demand
- Hold four days of heat (Rushforth LLC uses 2+ days... and gets much better results than one day)
- Basic Guidelines
- Place storage indoors...not outdoors, because heat loss indoors helps heat the building.
- Manufacturer
- STSS
- Communications with Brad @ STSS
- Tank Sizes
- Other:
- American Solar Solutions Comes on a pallet and you assemble...you can get it in the basement. Comes in 800 gallon tanks with heat exchangers.
- Design Tank Fiberglass tanks comes in sections
- STSS
- Preliminary Specifications
- Location of Storage
- Ground floor slab in addition bldg
- Create insulated room w/ R-25 walls + R-25 floor + R-25 ceiling
- Thermal Architecture
- All heat generators (i.e. solar and geothermal) connected to the storage
- All heat consumers (i.e radiant heat and domestic hot water) can draw heat from storage via heat exchangers.
- Size of storage
- Store 2 million BTU to start (3,500 gallons)
- Number of tanks: 1 - 3,500 gal
- Assume 1,500 gal
- Size: 3,500 gal = 10 ft dia x 7ft tall
- Capacity: 470cf
- Thermal Capacity:
- Winter: 3500 gals = 470cf = 2.3 mBTU: equivalent to approx 13 average winter days (almost two weeks)
- Summer: TBD
- Thermal Loss: R-19 around tank
- Flow Rate: Max 15g/m ... geothermal connection
- Pressure: Sealed, non-pressurized
- Fluid: Water...no additive
- Temp: Max: 175F Min: above radiant floor or indoor temp
- Location of Storage
- Open Issues
- Number of tanks? Use 1 tank due to cost of heat exchangers
- Do you need a small tank for the domestic hot water? Probably not....except for cooling season.
- What about using it for off-peak cooling storage for the geothermal? Haven't seen it done.
Radiant Floor
- Demand Requirements
- Areas: 8200sf Historic, 2xxx Annex
- See peak load in GG Solar Thermal Workbook
- Basic Guidelines
- Only 10% of heat is lost through the floor...42% through the roof
- Radiant heats up to about 7ft from the floor
- Manufacturer
- Radiantec from Vermont
- Others:
- Preliminary Specification
- Zones: approx 1100sf; 8 - Historic; 2 - Annex
- Circuits: 6 per zone
- Plex: 1/2in
- Spacing: 8in
- Flow Rate: 4.5 g/m
- Temp: normal winter operating 90F; max = 130F
- Thermal Capacity: 38,000 BTU/hr per zone
- Floor architecture
- Historic
- Vapor barrier or sealer (10mm?)
- Two layers of 1" XPS with seams staggered and sealed. (2")
- Reflective radiant barrier (could be foil on the XPS?) (mm)
- Sleepers (1.5") with metal heat extenders
- Plywood? Wood Flooring (1")
- All screwed together, run trenches
- Historic
- Open Issues
- Normal operating temps winter...summer? Winter = 90F max...summer = 68F min
- Can radiant floor be used for cooling? Yes see ASHRAE report ... min 68 degrees
- Plex sizing in Michigan code? Appears we can use 3/4"...1/2 min
Geothermal
- Preliminary Spec
- Location: Basement
- Connect Geothermal to with open loop to the mass storage
- Manufacturer
- Water Furnace...Envision
- Open Issues
- Geothermal - operating temps (min-max)
Resources
- Conversation with Alan Rushforth on April 2, 2008
- Overall
- Overall Concept ... recommends thermal storage.
- DOE Solar Liquid Heating
- Solar Thermal System Calculator Surpisingly sophisticated
- Natural Sun Heating - Mentor is Sunpower Designs from Laren Corie
- Build it Solar - wonderful resource for everything solar
- Dr. Shurcliff's 101 Solar Space Heating designs excellent common sense ideas for solar heating
- Passive ZED/Solar Heating Site
- Rushforth Solar LLC Solid consulting company in PA for solar heating.
- The Oil Drum forum