Archive for the ‘Passive Solar’ Category

turko with hat

by Turko Semmes

In the past, I have written before about Passive Solar Solutions for buildings. And still they are an important way to reduce energy costs and increase comfort levels. There are four components that must be considered when applying passive solar solutions to a project. They are Orientation, Ventilation, Insulation, and Mass (OVIM). Each part of the solution is used in different ways depending on the climate where the building is being built as well as certain site, budget and human factors. But by applying these applications appropriately, the building’s energy use can be greatly reduced. The comfort levels can be raised even in severe climate zones, sometimes at little extra cost.

Today, I want to talk about Mass, sometimes known as Thermal Mass. In particular, let’s discuss Phase Change Materials (PCM’s). The Thermal Mass role is to act as a battery to moderate the temperature of the home through the daily and seasonal cycle changes.

There are two applications of mass. One is direct gain where the sun strikes the material directly – think Trombe Wall systems.

The other and more common application is indirect gain. This is where the temperature of the mass is affected by the room temperature – think all surfaces in the building. We try to incorporate standard high mass materials into buildings to achieve this, but it is not always practical. Some of these materials are concrete in the floor, walls and counters. Also used are extra layers of drywall, fireplace facings, etc.

But for years, we in the industry have thought it would be super to have a material that can store more heat than its actual weight or volume. Now that material is here and it’s called Phase Change Materials (PCM). PCM’s can store 5 to 14 times more heat per unit volume than conventional storage materials such as water, masonry or rock. They do this by changing from a liquid to a solid (much like Freon does in heat pump/air conditioning systems). The trick has been to find a way to incorporate them into buildings in a format that can be standard for all buildings.

Now, the National Gypsum Company in partnership with BASF has ThermalCORE PCMmanufactured a drywall that has small capsules – beads of phase change material within the board. The drywall is installed and finished in the same ordinary way. The only extra cost is the material itself. But, don’t jump up and run down to Home Depot or Lowes. This material is in the economic and marketing development stages. However, I do have some samples, and they are performing quite well, as specified.

Soon, this material will give your energy analyst another tool to help design your building to be more energy efficient and comfortable. All without adding additional systems, complications or maintenance. Since drywall is used on most buildings, one can place it strategically to achieve the comfort and energy savings desired. This is just one more reason Passive Solar Solutions should be applied to their maximum potential before any active or complicated systems are considered.

Phase Change Materials for
Building Applications

 

 

Jessica by Jessica Steely

Imagine a power outage in your neighborhood, but your lights are on and your refrigerator’s running. Or perhaps you don’t have to buy expensive peak-day electricity? Elon Musk’s new Tesla Powerwall, released in April, promised these luxuries. The sleek and futuristic look of the wall-mounted batteries was designed to be affordable for the average homeowner. It’s available if you have a solar array or not, whether you want to use the battery on a daily basis, or have it available for a backup situation.

So, is the Tesla Powerwall a fiscally responsible choice or an expensive novelty?

Let’s take the case of the daily use model. Say, you’re on a net-metering program with your local electric tesla-powerall - tah-dahutility company. This summer’s peak rate is .32 cents per kWh (May 1 through October 31: Weekdays, 1-7 PM) and the off-peak rate is .13 cents per kWh. The winter partial-peak rate is .15 cents per kWh (November 1- April 30; Weekdays, 5-8 PM.) There’s no peak rate in winter, and the off partial-peak rate is .14 cents per kWh. The Powerwall designed for daily use, holds 7 kWh and costs $3,000. If you use the Powerwall battery during peak-times when electric costs are higher, you will save $1.33 per day during the summer and .07 cents per day through the winter. At this rate, it could take you over 16 years to break even. The unit has a 10-year warranty, so even within the projected product lifespan you can’t expect to break even.[1] But with upcoming new regulations on power production, energy costs are likely to increase and the price recovery period could change significantly.

Now, let’s look at the units designed specifically for backup usage. These models carry 10 kWh of backup Tesla Powerwall -Housepower with an available average draw of 2 kW. Their cost: $3,500. These batteries are compared to a small generator that runs on gas or propane. A generator that produces equivalent output can be bought from your hardware store for $500 to $1,500. With propane at roughly $2.24 per gallon and gas at $4.25 per gallon, the cost to run these backup generators is variable. Again, it is likely to take longer than the 10-year warranty period to break even on the unit.

A couple of additional caveats to consider: If your demand surpasses the needs of a single battery, each of the models of the Powerwall can be installed in a bank of up to nine batteries. They can also be installed in conjunction with a solar electric array. But if the unit is installed outside of a solar electric system, you will have the additional cost of purchasing an inverter to convert the electricity from AC to DC for usage and storage. It is worth acknowledging that the battery, designed to cycle on a daily basis, could provide the added utility of serving as an emergency backup.

From a financial perspective when compared to the alternatives, the Tesla PoTesla Powerwallwerwall is not the most economical response…yet. However, the sense of being part of a progressive movement, having a renewable energy backup and helping to reduce the strain on our utility grid, has attracted more than 38,000[2] reservations for the Tesla Powerwall in the first week of its announced release. It’s projected to be sold-out by mid-2016. I doubt we have seen the last from Tesla’s technology center, but I do look forward to what’s next.

 

[1] Rates are based on PG&E Tier 1 Residential Time-Of-Use Service Electric Schedule E-6 effective March 1 2015  http://www.pge.com/tariffs/tm2/pdf/ELEC_SCHEDS_E-6.pdf

[2] Bloomberg Business Tesla’s Battery Grabbed $800 Million in Its First Week, 5-8-2015 http://www.bloomberg.com/news/articles/2015-05-08/tesla-s-battery-grabbed-800-million-in-its-first-week

Kevin-HauberSpecial editorial by Kevin Hauber, Green Mortgage Consultant
The Mortgage House – San Luis Obispo

Remember all the claims made by solar companies about the value of rooftop solar systems? Well, it turns out they were right. And a study out from the US Department of Energy and Lawrence Berkeley National Laboratory backs that up. The study is called “Selling Into the Sun: Price Premium Analysis of a Multi-State Dataset of Solar Homes.”

What they did was look at tens of thousands of sales over eight states from 2002-2013, including properties that had solar systems installed at the time of sale and those that did not. What they found was that both new and existing homes sold for $15,000 more on average with a solar system than those that did not have one.

That is a noticeable number. It’s one of the first times substantial figures have been offered to quantify solar homes for the market. It says that if you can lower the operating costs of a home and provide energy independence, that’s worth something.

Selling into the sun

Selling into the Sun

So, everyone knows this. Right?

No, in fact very few people take this into account. If you are going to buy or sell a property with a solar system, you need to make sure the people involved in the transaction are familiar with how to give the system value. That includes the listing agent, the selling realtor, the lender, and the appraiser. The appraiser will use a form called the energy addendum to help quantify the value of the solar system. As well as any other energy related improvements on the property.

You would be surprised how many appraisers have no idea about this, and how many lenders and realtors don’t even know to ask. Since energy costs are becoming an increasing consideration for owning property, make sure you are working with professionals who know what they are doing in this regard. This includes familiarity with the incentives and financing available for energy-related improvements.

By the way, the figures quoted in the study are only for purchased solar systems that are part of the real estate. Leased systems were not included in the study, so this is an important distinction to make. Leased systems have become popular in the last few years, but there are still many questions to be answered. Such as the assumption of leases by subsequent buyers, and the appraised value of the system at the end of the lease. (The appraiser is usually hired by the leasing company). The effects of these leased systems remain to be seen.

Now this research concludes what we’ve assumed all along: people who have purchased solar systems for their homes and businesses have made a substantial investment that has lasting value.

Hilltop-Adobe-16-1024x682 The beautiful, sustainable home designed by owner, Richard Soundy and built by Semmes & Co Builders, Inc. was featured in the Tribune. The article gives a great description of the home and all of it’s passive solar features.

Check out the design and its views here.

 

swells-1

 

This Coast Range home is just about ready to have the windows installed.  This small residence is super insulated with double studs that make no contact from the inside to the outside. When you take an infrared photo of this home no studs will show up and in general it will be blue……………..These walls will have an R value of 38 with no conduction except at the openings! Keep your eyes here to see how this project progresses.