The Denver Zoning Code has been rewritten, and is on the verge of release for public comment. The issue of Solar Access has been put on hold for at least a few months. This is understandable, as the release of a large, important document like this is very difficult.
Unfortunately, solar systems are being built in Denver with no protections against shading from neighbors.
For more, please see read this document:
Solar Access for Denver Neighborhoods
Tuesday, April 14, 2009
Friday, March 27, 2009
Connecting the Dots Between Google and the Smart Grid
How the Google Math Adds Up:
1. Google is rapidly becoming the nation's largest single consumer of electrical energy.
2. 2007: Google announces their goal of producing renewable (solar) electricity as cheap as coal. The goal: $ 0.025/kwh
3. Plentiful solar electricity is generated during the common peak demand periods, hot summer afternoons.
4. 2009: Google announces the PowerMeter to help implement the "smart grid" as they envision it. A properly implemented smart grid could increase the selling price of peak demand power to $ 0.25/kwh or more.
Therefore, #4 causes a 3x to 10x increase in the profits of #2, while #3 + #2 solves problem #1.
1. Google is rapidly becoming the nation's largest single consumer of electrical energy.
2. 2007: Google announces their goal of producing renewable (solar) electricity as cheap as coal. The goal: $ 0.025/kwh
3. Plentiful solar electricity is generated during the common peak demand periods, hot summer afternoons.
4. 2009: Google announces the PowerMeter to help implement the "smart grid" as they envision it. A properly implemented smart grid could increase the selling price of peak demand power to $ 0.25/kwh or more.
Therefore, #4 causes a 3x to 10x increase in the profits of #2, while #3 + #2 solves problem #1.
The Return of the Carriage House, Denver 2009
Detached accessory dwelling units will apparently be allowed in Denver's new zoning code. The sustainability benefits are so numerous that ADU's tend to be the darling of city planning staffs nationwide.
The following article was written by Becky Alexis, a Platt Park architect involved in sensitive redevelopment.
"The carriage house has been a part of our built environment since the beginning of the twentieth century. Found everywhere in our community from Country Club homes to low income areas, the accessory dwelling unit has historically provided home owners needed flexibility for guests, expanded family, boarding and household help. Today our need for a sustainable housing sector is eased if home owners have the same opportunity. By converting the rear zone of a property into the highest and best use, families, neighborhoods and municipalities benefit socially, economically and environmentally.
Giving home owners the opportunity to add functional value to their property helps all socio-economic levels. From the first time home buyer to the elderly, the added dwelling space helps all owner-occupants to stay in their home. Fabrication is less costly than conventional housing and uses include family living, child and elderly caregivers, workspace and rental income. This flexible space affords opportunity for families’ changing needs in a time where the risk of home loss is high. As a work space, the detached dwelling reduces costly commuting requirements. The building form adds security and beautification to the alley and creates intimate and properly scaled courtyards which require less water and maintenance needs. Simply, the carriage house aids in preserving single family living.
Keeping families in their home is critical for the stability of neighborhoods. Less housing turn-over means less speculator driven scrape-offs, and a preservation of the neighborhood character. The added benefit of a carriage house to a property increases the value of other homes in the area. The added activity also reduces crime, especially in the most vulnerable space, the alley. Conceived as 800-1200 s.f. apartments over a 2-3 bay garage, these units reduce existing and future off-street parking demand. Safety, secured property values, and an improved built environment make the neighborhood more livable and desirable for existing and new residents.
To the municipality, this non-obtrusive densification of our neighborhoods has numerous benefits. The existing utility infrastructure is currently under utilized, so adding more dwellings would be accommodated and would add a larger tax base to support the existing infrastructure. Families would not be financially forced into the suburbs. Children could stay at their schools. Commuting by vehicle would be minimized, and our local public transportation would be better utilized. Jobs would be created by the people that build these structures and by the folks that choose to work out of them. It is a win-win situation that reduces stress on families, reduces falling house prices, minimizes scrape-offs which fill our landfills, reduces water needs with more sensible backyards, and reduces our carbon footprint.
Denver’s own Peter Park, the City Planning Manager, has said, “When cities stop changing, they start dying.” This is a “Shovel-ready” opportunity for good design and correct context to fulfill real and perceived needs."
-Becky Alexis, HIVE Architecture, LLC
The following article was written by Becky Alexis, a Platt Park architect involved in sensitive redevelopment.
"The carriage house has been a part of our built environment since the beginning of the twentieth century. Found everywhere in our community from Country Club homes to low income areas, the accessory dwelling unit has historically provided home owners needed flexibility for guests, expanded family, boarding and household help. Today our need for a sustainable housing sector is eased if home owners have the same opportunity. By converting the rear zone of a property into the highest and best use, families, neighborhoods and municipalities benefit socially, economically and environmentally.
Giving home owners the opportunity to add functional value to their property helps all socio-economic levels. From the first time home buyer to the elderly, the added dwelling space helps all owner-occupants to stay in their home. Fabrication is less costly than conventional housing and uses include family living, child and elderly caregivers, workspace and rental income. This flexible space affords opportunity for families’ changing needs in a time where the risk of home loss is high. As a work space, the detached dwelling reduces costly commuting requirements. The building form adds security and beautification to the alley and creates intimate and properly scaled courtyards which require less water and maintenance needs. Simply, the carriage house aids in preserving single family living.
Keeping families in their home is critical for the stability of neighborhoods. Less housing turn-over means less speculator driven scrape-offs, and a preservation of the neighborhood character. The added benefit of a carriage house to a property increases the value of other homes in the area. The added activity also reduces crime, especially in the most vulnerable space, the alley. Conceived as 800-1200 s.f. apartments over a 2-3 bay garage, these units reduce existing and future off-street parking demand. Safety, secured property values, and an improved built environment make the neighborhood more livable and desirable for existing and new residents.
To the municipality, this non-obtrusive densification of our neighborhoods has numerous benefits. The existing utility infrastructure is currently under utilized, so adding more dwellings would be accommodated and would add a larger tax base to support the existing infrastructure. Families would not be financially forced into the suburbs. Children could stay at their schools. Commuting by vehicle would be minimized, and our local public transportation would be better utilized. Jobs would be created by the people that build these structures and by the folks that choose to work out of them. It is a win-win situation that reduces stress on families, reduces falling house prices, minimizes scrape-offs which fill our landfills, reduces water needs with more sensible backyards, and reduces our carbon footprint.
Denver’s own Peter Park, the City Planning Manager, has said, “When cities stop changing, they start dying.” This is a “Shovel-ready” opportunity for good design and correct context to fulfill real and perceived needs."
-Becky Alexis, HIVE Architecture, LLC
Thursday, February 26, 2009
Polymer ISC Solar Collector Debuts
Just a few days after my post about passive solar thermal water heating, the grandson of the Arthur D. Little collector design came to my attention. Called the Solar Cache by Harpiris Energy, it has been designed only for non-freezing climates. With PEX pipe, which may be considered freeze tolerant, this will be a great product for economy installations, costing far less than the usual $6k solar DHW systems for freezing climates.
I just hope it doesn't get installed in colder climates, freeze, burst and give the product a bad name. When drain-down systems were used in Denver in the 80's, many an attic was flooded because of Murphy's Law. Even though there were freeze protection controls and backup freeze protection controls, they still failed.
Ironically, a common complaint from solar DHW system owners may cause pumps to appear in these passive systems. See, most systems have a solar preheat tank (with the Sun Cache the solar tank is on the roof), and a backup (fossil fuel) tank piped downstream in series. If the homeowner doesn't consume any hot water (like all day when he's at work) then the backup tank fires to make up for standyby losses, even though the preheat tank may be 140F or higher. In the summer, a solar system should be providing 100% of the hot water load on sunny days, so some homeowners get peeved when their gas bill isn't zero and the backup tank is coming on every hour or so. A really tiny recirculating pump with a simple control is a way to prevent the problem, but now you've added a pump to an otherwise elegantly simple system. The other beef with the "uninsulated" storage tank on the roof is that you'll never have any solar hot water left for the morning shower, the storage water will drop close to outdoor ambient by morning.
Rheem has also come out with a passive collector with some freeze tolerance. The collector loop is charged with antifreeze. Again, great care should be used on the supply pipe, even in "non-freezing" climates.
Sunday, February 8, 2009
Hail Resistive Roof Saves on Insurance
State Farm just started putting this line on my insurance declaration page:
Premium Reduction:
Hail Resistive Roof: $521/yr.
My roof is a spanish tile look-alike made of stone coated steel from Gerard
I don't know if clay-based or concrete tile roofing qualifies for the discount, which is about 30%. Both of those systems, however, require a significantly stronger roof structure due to the higher dead load. (edited 2/10)
So, I got a premium-looking roof that pays for itself in ten years compared to asphalt shingles.
It's a very green choice because the steel is recyclable, and guaranteed for 50 years.
Friday, February 6, 2009
Green Roofs?
I have remained on the sidelines with regard to promoting green roofs. I'm hesitant partly because many people in the multifamily industry have this saying that goes "flat roofs always leak".
In my own experience, the most frequent and worst leaks occur at the low spots where ponding occurs. A pond on your roof causes dust in the air to stick to the surface of the water. Over time, this dust builds up and starts looking like dirt, or soil. Seeds get blown into this muck, and sprout. I know this is a poorly designed ad-hoc green roof, but the fact remains that leaks never start in the dry spots on flat roofs.
I guess some sort of roof garden would be nice if you also had a roof deck and actually used it.
I'll let Dr. Joe L., every building scientist's hero, explain it:
"Green roofs? Grass and dirt are not energy efficient.Work with me here. Which saves more energy—2 inches of dirt or 2 inches of insulation? Which saves more energy—grass or a white colored membrane? Which is more expensive and does not save energy—grass and dirt or insulation and a white colored membrane? Which needs to be watered to keep the grass from dying and blowing away? But they are beautiful and look cool. And that apparently is more important than cost and energy savings. Okay, I can live with the beautiful and looking cool argument if that is in fact the argument—but don’t clutter it with half-truths such as heat island effects and water run-off. There are other (better) ways to deal with each."
He goes on to admit he won't win the argument, so he provides the proper drawing detail that works.
In semi-arid Denver, I'll posit that the money spent for the water needed to keep your roof alive will be far more than the dollar value of any perceived benefit.
In my own experience, the most frequent and worst leaks occur at the low spots where ponding occurs. A pond on your roof causes dust in the air to stick to the surface of the water. Over time, this dust builds up and starts looking like dirt, or soil. Seeds get blown into this muck, and sprout. I know this is a poorly designed ad-hoc green roof, but the fact remains that leaks never start in the dry spots on flat roofs.
I guess some sort of roof garden would be nice if you also had a roof deck and actually used it.
I'll let Dr. Joe L., every building scientist's hero, explain it:
"Green roofs? Grass and dirt are not energy efficient.Work with me here. Which saves more energy—2 inches of dirt or 2 inches of insulation? Which saves more energy—grass or a white colored membrane? Which is more expensive and does not save energy—grass and dirt or insulation and a white colored membrane? Which needs to be watered to keep the grass from dying and blowing away? But they are beautiful and look cool. And that apparently is more important than cost and energy savings. Okay, I can live with the beautiful and looking cool argument if that is in fact the argument—but don’t clutter it with half-truths such as heat island effects and water run-off. There are other (better) ways to deal with each."
He goes on to admit he won't win the argument, so he provides the proper drawing detail that works.
In semi-arid Denver, I'll posit that the money spent for the water needed to keep your roof alive will be far more than the dollar value of any perceived benefit.
Thursday, February 5, 2009
Passive Solar DHW
To some, the holy grail of solar thermal is a system without pumps and controls.
Himin of China manufactures a nice one:
At Solaron in the '80's, we purchased the manufacturing rights to a passive DHW design developed by Arthur D. Little. The problem was that the pipes going to the collector would freeze in the winter. Frozen pipes in the attic were so undesirable and difficult to eliminate that we ultimately abandoned the whole project. As far as I know, no one is pursuing this type of design in northern climates.
Now that building codes are beginning to actually recommend insulated roof planes and conditioned attics, the Chinese design looks very interesting. The pipes in the attic won't freeze because the attic is inside the house envelope. As long as the piping to the roof-mounted tank is kept extremely short, it won't freeze either. Natural convection within the pipe and heat conduction along the pipe from the tank and the attic area would prevent freezing.
Note that there is no water in the evacuated tubes, so they won't freeze. All the usual overheating issues have also been solved passively.
From Arthur D. Little, we also learned that the roof-mounted tank will never approach freezing temperatures anywhere in the continental US. (Basically there's enough solar insolation even on completely cloudy days to keep the tank above 40 degrees)
The main attraction of this design is that system efficiencies are far superior to pumped designs. Also, with no moving parts to fail, the life-cycle cost is held low, and the ROI is maximized.
Himin of China manufactures a nice one:
At Solaron in the '80's, we purchased the manufacturing rights to a passive DHW design developed by Arthur D. Little. The problem was that the pipes going to the collector would freeze in the winter. Frozen pipes in the attic were so undesirable and difficult to eliminate that we ultimately abandoned the whole project. As far as I know, no one is pursuing this type of design in northern climates.
Now that building codes are beginning to actually recommend insulated roof planes and conditioned attics, the Chinese design looks very interesting. The pipes in the attic won't freeze because the attic is inside the house envelope. As long as the piping to the roof-mounted tank is kept extremely short, it won't freeze either. Natural convection within the pipe and heat conduction along the pipe from the tank and the attic area would prevent freezing.
Note that there is no water in the evacuated tubes, so they won't freeze. All the usual overheating issues have also been solved passively.
From Arthur D. Little, we also learned that the roof-mounted tank will never approach freezing temperatures anywhere in the continental US. (Basically there's enough solar insolation even on completely cloudy days to keep the tank above 40 degrees)
The main attraction of this design is that system efficiencies are far superior to pumped designs. Also, with no moving parts to fail, the life-cycle cost is held low, and the ROI is maximized.
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