Heating Help

fine

@ April 4, 2011 8:27 PM in FredSolar

FWIW, I really like my SSU-119. It's in a glycol system. Works great.

yup

@ March 29, 2011 9:06 PM in radiant heat and electric usage

Constant circ system. $0.21/kWh. From $140/season to $11.....

wastage!

@ March 28, 2011 10:23 PM in radiant heat and electric usage

Yes indeed, Mark.

In my house, the overpumping yielded an over-electrical consumption of 93%. Upgrading to Alpha went to 12 Watts from 163 Watts. Simply amazing. Simple payback in ~3 heating seasons.

sizing?

@ March 19, 2011 8:48 PM in Weil Mclain Ultra constant problems

155 is a pretty big boiler. Single zone with no indirect? Did anyone do a heat loss calc to size this?

steca

@ March 11, 2011 9:46 PM in Drainback design questions

Been following this thread with interest.

I have a simple SDHW system with an SSU-119 and Steca 0301U. Love the SSU-119, matched to 80 sf of collector at 41 north. Works great.

The Steca is a very, very simple 3 input, one output differential control. If I had to do it again, I'd go with a variable speed control like a tekmar 157 or one of the Caleffi's as has been suggested. I suspect the Steca might be a bit simple for what you need to do, particularly if you need to control anything else. But if not, the control has been solid for just about 3 yr and has very low power draw.

Good luck. Sounds like a great project.

p.s. Nice hats!

energy diet! and performance, too!

@ February 26, 2011 10:06 AM in The Biggest Loser

Amazing stuff, these ECM pumps. Thanks Dave for the great article, and everybody else for the additional insight in the posts.

Just reduced the electrical cost by 93% for a constant circ baseboard system. Went from 163 Watts to 12. Simple payback in 3 heating seasons.

Flow rate reduced to around 2 gpm from whatever it was before. Finally have a reasonable deltaT where almost none existed before. Structure heats beautifully.

setup

@ February 20, 2011 7:05 PM in sizing indirect for solar post-heat

Thanks Brad.

The setup is:

cold domestic supply goes into solar tank (120 gal). Hot solar out goes to manual 3-way valve where it either goes direct  to taps (April-October), or to indirect 'cold' supply, where it is trimmed up and then out to taps.

That help?

I have played a little with running the summer production through the indirect with boiler shut down. Sort of raises effective capacity over the 120 gal solar itself, and keeps the bottom of the solar tank cooler and better stratified. But the 40 gal additional 'storage' can cool off depending on solar feed temp and time between major usages.

sizing indirect for solar post-heat

@ February 20, 2011 9:41 AM in sizing indirect for solar post-heat

Have a solar DHW system that needs boiler supplement in winter. Typical worst case lowest tank temps around 75F. Average temp rise required around 40-50F.

System is piped with a 3-way valve that allows seasonal SDHW only, and winter SDHW output to boiler-fired indirect (a tired old poor performer).

Existing boiler is 84k output with DHW priority control.

Question is whether to go with smallish 20 gal indirect (e.g., SSU-20) and shoot for basically continuous hot flow capability assuming fairly low temp rise, or go with larger indirect that does more 'standard' dump-and-recover service.

Thoughts appreciated.

TIA

TEL

@ January 29, 2011 9:00 PM in Taco pump problem

If you followed the Selecting Circulators approach, and came up with 225 feet of equivalent length for your longest zone, then....

For TEL = 225 ft

gpm    head(ft)   
3.5    5.55
4    7.01
4.5    8.61
5    10.35
6    14.24

So you can flow 4 gpm at 7 ft of head. Taco 007 would be fine for typical residential application (and with that you might be up around 5gpm; perhaps a bit much). Or go with the Grundfos 15-58 if you want to play with speeds. Or go fancy with an ECO or Alpha if you want lower electric use and some pump 'smarts'.

here tis

@ December 29, 2010 9:25 PM in Outdoor reset wind sensor?

http://www.tekmarcontrols.com/sb/sb018.pdf

the envelope, please

@ December 29, 2010 8:24 PM in Outdoor reset wind sensor?

First, do whatever you can for the building envelope to reduce infiltration. For what some of the tech approaches here might cost, you could do a whole lot with a canister of two-part foam and some caulk. Recently worked with some seniors in a drafty house. One tube of caulk solved a whole bunch of problems in a day room.

Second, figure out a way to get bulk indoor sensing. You can ladder indoor sensors with tekmar gear to get an average. The air sealing will help drive all the rooms toward that average. Do you have a spare pair of wires in the thermostat runs? Also like the idea of a wireless solution. Maybe ask tekmar what they suggest.

Indoor sensing integrates all the various losses and gains. The indoor temperature and its trends define the load. So when you have a party on a cloudless night, your heating system doesn't overheat due to the 20 people (at 200-250 BTU/hr each) in your house. :)

do it for yourself

@ November 2, 2010 6:57 AM in Heat Loss Calc. For Forced Hot Water Replacement Boiler?

Your business, that is.

Heat loss calcs are a) the right way to size a boiler, b) increasingly required by some jurisdictions, c) often required to qualify for utility rebates.

Doing a heat loss on your jobs distinguishes you from nearly all of your competition. It shows the customer that you have their best long-term interests in mind. Proper sizing leads to better performance and long-term energy savings. Tell that to the customer.

Get familiar with some heat loss software. With practice, it only takes an hour to do one. It's ok to charge for the service. Credit the fee toward the install if you get the job.

As others have noted, length of baseboard has essentially nothing to do with boiler sizing. Maybe it was sized originally, maybe not.

The past couple years have also seen a huge increase in people doing weatherization/insulation/air-sealing upgrades to their homes and businesses. In many cases this drastically reduces the heat loss, so you can downsize the boiler, or go with a modcon to take advantage of the excess baseboard capacity by using lower water temperatures and outdoor reset. Tell your customer about the economics and comfort. Show them that their work to reduce fuel costs by insulating has a real benefit by reducing boiler size or going with much more efficient modcon.

Make them feel good about your professional approach, and your interest in providing a quality service that ultimately saves them money.

thanks

@ October 22, 2010 7:14 AM in electric to tankless propane conversion?

All under consideration. Thanks.

electric to tankless propane conversion?

@ October 17, 2010 9:56 PM in electric to tankless propane conversion?

Doing some remote consulting on a DHW retrofit. Long story….

This setup is not providing desired efficiency and
performance. It serves 3 bathrooms, one kitchen, one laundry. But 2 of the bathrooms are used maybe a week per year.

Current situation is as pictured, two electric tanks, piped
in a way that I really don’t get. Apparently there used to be one tank serving
the two upstairs baths, and one serving rest of house. Now??

Recirc, obviously.

There is interest in converting to propane-fired tankless. Probably Rinnai, but open to suggestions. No significant dump loads (2.5 gpm showerheads, laundry, dishwasher; seldom if ever used all at once).

The current setup is in an attic space over an attached
garage.  Points of use are 20-50 ft away.

Can provide more info as necessary.

Thanks.

great stuff

@ September 29, 2010 9:03 PM in OT: gas dryer basics

Wow. Thanks guys for the great perspectives. It's going in shortly.

The guts do look simple (modular, anyway), and not impossible to access.

The actual numbers pencil out pretty much as Brad described. Just a hair less favorable, but still impressive.

The space in question has no other appliances requiring combustion air, and it will have plenty. And short, all rigid exhausting.

Thanks again.

cool!

@ September 28, 2010 9:49 PM in ventilating after weatherization

Hi Brad,

Great to see you back on the Wall. 30 cfm is exactly what my local guru came up with. Probably using the same software....

We used that figure as the starting point for the end of last heating season, and it seems to work well.

Thanks!

OT: gas dryer basics

@ September 27, 2010 10:53 PM in OT: gas dryer basics

So what's the deal with gas dryers? Just saw one. Says 20k BTU/hr input, but no idea what combustion efficiency might be, whether it's fixed fire or not, etc.

And whether it's reliable and/or more efficient over the long haul than an electric.

Any insight appreciated. TIA.

how about...

@ September 13, 2010 8:32 PM in build new house ....radiant heat?

Panel radiators, piped home-run with TRVs or stats.

Simple, easy to (over)size for lower water temps, easy to pipe, comfortable, etc.

go condensing, but...

@ September 9, 2010 8:13 PM in Condensing Boiler with Tube & Fin radiant system???

I have a house full of fin-tube. It never goes above 135F supply, even at 5F outside. It was originally sized for 180F at 5F outside. Most of the year it runs between 80-115. Works great, using an outdoor reset control and indoor feedback. House is incredibly comfortable, second only to the radiant house I grew up in.

Now for the buts....

1) An 1890 house has HUGE room for improvement to reduce heat loss and thus energy required to heat it. Like 50% or more. Reducing heat loss through insulation and air sealing is the simplest and most cost-effective way to save energy and improve comfort. Start with a blower door test and thermal IR imagery done by a professional contractor and develop an insulation and air sealing plan from that. There are good federal tax credits for weatherization. Often state and utility programs as well. Check www.dsireusa.org for list of things in VA.

As you reduce the heat loss, you reduce the supply water temperature needed to heat the house. So now you can be condensing nearly all year long and reaping the extra efficiency of the modcon.

2) Others may disagree, but IMHO the aluminum-block heat exchangers are bested by the stainless (there are many manufacturers and models from which to choose -- find a good installer). The aluminum based systems are more sensitive to system water chemistry, which needs to be checked, maintained, etc. among other things.

Good luck.

even a bit

@ September 1, 2010 10:20 PM in Boiler Sizing

And to follow on Dave Yates' sage advice, if you can do even just a little air sealing and insulation, you get into the smaller modcon realm. The smaller you can go, the better. Take advantage of lower modulation rates for the shoulder seasons and above-design temperature days that comprise 95+% of the heating season. For example, if you can get down to a 10-50k or 15-60k BTU/hr modcon instead of a 19-80k BTU/hr model, that's great.

Also check out federal and state tax credits for high-efficiency equipment, as well as utility rebates. www.dsireusa.org keeps a great listing. This can often drop the cost of a good modcon install down to what a simple fixed-fire boiler install would be.

stretch it another year

@ September 1, 2010 9:21 PM in Boiler Sizing

Reducing household energy use starts with conservation, then efficiency. I suggest living with the oil-sucking monstrosity for another year and putting your money into  totally unglamorous but far more economic improvements to the building envelope (insulation and air sealing) to reduce the heating load. The best $200-400 you can spend is a blower door test with thermal IR imagery to evaluate the insulation and leakage of your building. Then do as much insulation and air sealing as you can. The idea is to reduce the heating load. 1600 sf and 68k BTU/hr heat loss is a really leaky, poorly insulated building. It needs help. Think of insulation and air sealing as fuel you buy only once. It pays back quickly and forever.

Once you improve the building and reduce the heating load -- perhaps by as much as half -- then start thinking about new, much smaller boiler that will have lower first cost and lower long-term cost.



A useful way to think about this is the efficiency pyramid:



http://www.greenbuildingadvisor.com/blogs/dept/musings/energy-efficiency-pyramid



Start at the bottom and work your way up. It's a useful and practical
model. I do take some exception to the text of the article, however. In
many places renewables are heavily subsidized which makes their
economics a lot better and thus would move them down the pyramid. But as
a general guide this is a great place to start. Note that heating
systems come after a lot of other conservation and efficiency work.

efficiency

@ September 1, 2010 9:09 PM in Higher Efficiency Pumps & Motors?

Household energy starts with conservation, then efficiency. If you've looked at renewables, and are now considering heating system, that implies that you have already done all the totally unsexy but utterly critical improvements to the building envelope.

A useful way to think about this is the efficiency pyramid:

http://www.greenbuildingadvisor.com/blogs/dept/musings/energy-efficiency-pyramid

Start at the bottom and work your way up. It's a useful and practical model. I do take some exception to the text of the article, however. In many places renewables are heavily subsidized which makes their economics a lot better and thus would move them down the pyramid. But as a general guide this is a great place to start. Note that heating systems come after a lot of other conservation and efficiency work.