Dennis Houghton's Comments

March 18, 2014

Meet Solar’s Imaginary Friend, Reactive Power

@ PJ Van Staten
Thanks for the clever metaphor
"Thus in short, perhaps we find ourselves at a point where we should be "capacitive" (thinking leads action) and not be "inductive" (thinking lags action)."
As a technical instructor for apprentice electricians I am sure I will use the basic idea to convey a complex concept, so thanks again.

March 19, 2014

Meet Solar’s Imaginary Friend, Reactive Power

Most small PV systems produce "single phase" AC (120-240VAC). Almost all utility distribution is "three phase". This seemingly arcane difference poses a fundamental problem for residential PV providing realtime "reactive power" with any real value.
If one neighborhood widely adopts solar PV, AND, is served served by a single phase utility extension, then it is possible that a phase imbalance will be injected into the three-phase system. Upstream motor loads can be significantly impaired. Three phase motors rely upon a very precise electro-magnetic phase shift to rotate and deliver torque. A 3% (@10 degrees of rotation) phase shift can cause a three-phase motor efficiency drop to 90% or less. Very precise control functions would be required (not yet invented) to manage single phase reactive power sources. Fifteen years from today, maybe.

March 11, 2014

Energy Efficiency Ain't Got No Respect

Industrial and commercial facility managers:
From the article. Around 50% of all power consumed is used by electric motors.
If you have electric motor applications including pumps, fans and compressors which use modulating dampers or valves to control pressure or flow, you might realize a 40-50% drop in the power consumption by using VFDs on those motors, and modifying the dampers or valves.
Tens of millions of Variable Frequency Drives have been installed in the last decade.
Even in China, dozens of coal-fired power plants remain on the drawing boards.
Energy consumption per unit of production has been reduced in many industries.

The VFD is not magic, in fact the solar PV industry has adopted the name of its primary component, the inverter, for a major system component. A VFD typically has three functional stages. A three phase rectifier producing pulsating DC from 60Hz AC. A DC filtering section with inductors and capacitors which produces a smooth DC waveform, similar to PV output. An inverter comprised of (6) IGBTs controlled by a microprocessor. The AC source allows voltage manipulation through transformers and the DC output is both frequency and voltage controlled. Motors work better, run cooler and last longer. It is easy to ramp the starts so belts are preserved for years instead of months.
Less than three year payback without any subsidies. Permanent baseload reduction. Reduced demand charge exposure.

Almost all of your local HVAC and electrical contractors know about these devices.

March 04, 2014

Guessing Game: Tesla's Gigafactory and Energy Storage Aims

Elon Musk is today's Howard Hughes, without the fingernails. Yet!
Obviously a brilliant visionary with gobs of money, like Howard Hughes.
He has already contributed to the advance of global industry, like Howard Hughes.
He may spend large amounts of his own and other people's money on boondoggles, like Howard Hughes.
I hope he does not die incredibly rich and very insane, like Howard Hughes.

February 27, 2014

Musk’s Planned $5 Billion Tesla Battery Gigafactory May Unleash Bidding War

Although Lithium is far lighter than lead, a "gigafactory" will probably develop as a distributed system of extraction, production and distribution facilities which meet market demands.
Transportation costs are a significant portion of battery cost, even lithium ion.

The transportation infrastructure is a nationwide distributed network of interconnected nodes, aka the interstate highway system.

Electric vehicles will rely on a local/regional network of support infrastructure; a modification of the gasoline service station model, perhaps even piggybacked on that model.

Battery pack quick change out to fully charged battery pack in less than 15 minutes.
Battery charging systems which recharge the onboard battery pack in less than 15 minutes.
Decent fast food restaurant which feeds you in less than 15 minutes.
Placed at intervals of 50% of the advertised range of the typical electric vehicle.

February 26, 2014

Ask the Expert: Do Ground-source Heat Pumps Raise Your Electricity Use?

Mr. Stenswick,
The title to this article is really smart.
It has attracted several articulate thinkers, including you, who post consistently informative comments.
Other than that, I agree with what you say.

The article does do a pretty good job of answering the question posed by the title.

February 23, 2014

Three Strategies for Low-Income Solar Programs

Mr French,
You seem to be describing a basic DC circuit with a voltage source, a resistance load and circuit conductors to carry the current. Basic Ohm's Law, so yes it is feasible but perhaps not very useful. The heat you produce will be proportional to the current output of your solar array. Heat exchange efficiency is inversely proportional to temperature difference, which will continuously vary widely.
Solar PV produced electricity is too valuable to power resistance heat. Fans, pumps and control systems are much more useful applications for electricity.
If you want warm water use a solar thermal collector and a storage tank and PV powered pump. If you want heated air use the same equipment with a heat exchanger.

February 06, 2014

Are Air Source Heat Pumps a Threat to Geothermal Heat Pump Suppliers?

A decade ago, electric motors consumed almost 60% of all the electrical power produced in the world. The efficiencies introduced by rapid improvement and drop in cost in Variable Frequency Drives (VFD) have reduced that number to less than 50% today. Datacenters have taken up some of that lost consumption and the utilities are grateful.
Variable Motor applications such as fans, pumps and compressors can operate properly with as much as a 50% drop in power consumption. Twenty years ago the energy would have been wasted with valves and dampers, now it is simply not used. System performance was usually improved, especially in HVAC and water pumping systems. Ground source heat pumps benefit from the same VFD technology so it is not really a competitive edge for air source systems. Total system cost remains the air source systems competitive edge.

February 10, 2014

Are Air Source Heat Pumps a Threat to Geothermal Heat Pump Suppliers?

Back in the bad ole days, @40 years, an engineer might greatly over-design a HVAC system just to guarantee it would work in the absolute worst case conditions. Electrical power was cheap (too cheap to meter) and equipment and skilled labor were relatively inexpensive. Reputation was more important than cost.
Conditions are very different today. Reputations are built upon cost control through energy management.
Resistance heat is a wise substitute for gross over-design in any installation, particularly at the residential level.
Resistance heating can be augmented or even replaced by alternate heat sources.
Living "off-grid" with a dependency upon a large electrical machine poses a small irony in any case.

February 03, 2014

Tesla Revs Up China Electric Vehicle Engine

At the risk of displaying nit-pickyness, the headline speaks of an engine while touting a breakthrough development which has an electric motor not an internal combustion engine. Language is important. I understand that the headline refers to the metaphorical "economic engine" , perhaps it is time to refer to the metaphorical "economic motor"? All change is awkward.

January 19, 2014

It’s Cold and My Car is Buried in Snow; Is Global Warming Really Happening?

The power of language should not be underestimated. The transition to the widespread use of the phrase "global warming" to replace the descriptor of "climate change" coincides with the rise of profound climate change denialism. Warming and cooling are small-concept words usually applied to immediate circumstances, as Bill previously pointed out. Global is a big-concept word that will always provide an arguable exception to small-concept words. It is always cooling somewhere so that negates the "global" concept to small thinkers. (Most of us)
Climate is a big-concept word that is not well understood and is therefore equivalent to weather for most of us.
Change is another trap word that invites negation or approval without evidence.

As trite as it sounds, a big reason for the successful rise of non-scientific obfuscation and denialism is the use of the phrase "global warming". "Climate change" did not carry enough alarm with it. I suspect that the Denier Stream Media intentionally pushed the phrase for its power in their arguments.

Similar to "global warming", the phrase "residential warming" could mean that the sunshine just came through your window or that your furnace just started or that your house is burning down. We report, you decide!

I am waiting for someone to give most of us a phrase or demonstration that accurately demonstrates and explains entropy in an open and a closed system. Bill Nye recently gave that idea a good try with two bell jars, thermometers and some ice. It was too geeky for most of us.

Dennis Houghton

Dennis Houghton

Electrician instructor, Instrument technician, Electrical code inspector, Grid tied solar PV trainer, VFD application trainer

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