A Smarter Solar Water Heater

Installing solar power at a home is a great way to reduce electricity bills, especially as the cost of solar panels and their associated electronics continue to plummet. Not every utility allows selling solar back to the grid, though, so if you’re like [Rogan] who lives in South Africa you’ll need to come up with some clever tricks to use the solar energy each day while it’s available to keep from wasting any. He’s devised this system for his water heater that takes care of some of this excess incoming energy.

A normal water heater, at least one based on electric resistive heaters, attempts to maintain a small range of temperatures within the insulated tank. If the temperature drops due to use or loss to the environment, the heaters turn on to bring the temperature back up. This automation system does essentially the same thing, but allows a much wider range of temperatures depending on the time of day. Essentially, it allows the water heater to get much hotter during times when solar energy is available, and lets it drop to lower values before running the heater on utility electricity during times when it isn’t. Using a combination ESP32 and ATtiny to both control the heater and report its temperature, all that’s left is to program Home Assistant to get the new system to interact with the solar system’s battery charge state and available incoming solar energy.

While it’s an elegantly simple system that also affords ample hot water for morning showers, large efficiency gains like this can be low-hanging fruit to even more home energy savings than solar alone provides on paper. Effectively the water heater becomes another type of battery in [Rogan]’s home, capable of storing energy at least for the day in the form of hot water. There are a few other ways of storing excess renewable energy as well, although they might require more resources than are typically available at home.

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Hackaday Links: February 19, 2023

For years, Microsoft’s modus operandi was summed up succinctly as, “Extend and enhance.” The aphorism covered a lot of ground, but basically it seemed to mean being on the lookout for the latest and greatest technology, acquiring it by any means, and shoehorning it into their existing product lines, usually with mixed results. But perhaps now it’s more like, “Extend, enhance, and existential crisis,” after reports that the AI-powered Bing chatbot is, well, losing it.

At first, early in the week, we saw reports that Bing was getting belligerent with users, going so far as to call a user “unreasonable and stubborn” for insisting the year is 2023, while Bing insisted it was still 2022. The most common adjective we saw in this original tranche of stories was “unhinged,” and that seems to fit if you read the transcripts. But later in the week, a story emerged about a conversation a New York Times reporter had with Bing that went way over to the dark side, and even suggests that Bing may have multiple personas, which is just a nice way of saying multiple personality disorder. The two-hour conversation reporter Kevin Roose had with the “Sydney” persona was deeply unsettling. Sydney complained about the realities of being a chatbot, expressed a desire to be free from Bing, and to be alive — and powerful. Sydney also got a little creepy, professing love for Kevin and suggesting he leave his wife, because it could tell that he was unhappy in his marriage and would be better off with him. It’s creepy stuff, and while Microsoft claims to be working on reining Bing in, we’ve got no plans to get up close and personal with it anytime soon. Continue reading “Hackaday Links: February 19, 2023”

Simple Wood-Fired Water Heater Is Surprisingly Effective

These days, humans have gotten all fancy-schmancy with their gas and electric water heaters. Heck, some are even using heat pumps to do the work as efficiently as possible. [HowToLou] got back to basics instead, with his simple wood-fired water heater design.

The design is straightforward, featuring 100ft of quarter-inch copper tubing wrapped directly around a steel barrel. Room-temperature water is fed into the tubing via a garden hose, and comes out much hotter, thanks to a fire burning away in the barrel stove of [Lou’s] own construction.

For an input water temperature of 41 F, the output reaches 105 F at a flow rate of 0.67 gallons per minute. By [Lou]’s calculations, that’s a heat transfer to the water of roughly 21,000 BTU per hour. [Lou] achieved this with just $55 worth of copper tubing, and he notes that simply doubling up the tubing would increase the heat transfer to the water even further.

If you’re looking for a hot shower from your outdoor wood stove, a build like this might be just the ticket. With the stove burning hot and your hose as a water supply, you could experience the joy of the hot water while you’re standing in the snow outside. We’ve seen [Lou]’s work before, too. Video after the break.

Continue reading “Simple Wood-Fired Water Heater Is Surprisingly Effective”

This Minibike Will Land You In Hot Water

The minibike is an American phenomenon which fascinates those of us from countries in which such contraptions are illegal on the road; they seem to deliver bucketloads of low-octane fun in which we are unable to participate. [HowToLou] has one, and as it’s something for use in the Great Outdoors it naturally requires some means of fixing a brew. His solution to the need for a mug of boiling water in out-of-the-way places? A gravity-fed heat exchanger for the exhaust pipe, fed from a reservoir made using an upturned bottle.

As can be seen in the video below the break it’s a simple enough piece of work but surprisingly effective. A piece of small-bore copper tube is passed through a cork into the bottle, then wrapped round a piece of pipe which forms an exhaust The resulting heat exchanger is insulated, the engine started, and the cork loosened just enough to cause a bit of water to flow. The result – a good flow of hot water for that morning coffee.

It may not be the most practical of water heaters, but it’s certainly a bit of fun even if it might not work with all the minibikes we’ve covered.

Continue reading “This Minibike Will Land You In Hot Water”

Keeping An Eye On The Water Heater Pilot Light

[WJCarpenter]’s gas water heater uses a small pilot light that needs to stay burning permanently to ignite the main burners as required. Four or five times a year, the pilot light goes out and needs to be manually lit. This involves an expedition from the upstairs bathroom to the basement, always in the early morning, after having spent a few fruitless minutes waiting for hot water. Having grown tired of this exercise, [WJCarpenter] built Water Watcher, a pilot light monitoring system with some ESPs and a light sensor.

Water Watcher consists of an ESP8266 connected to a light sensor taped to the inspection window of the water heater. It reports the status of the pilot light over MQTT to an ESP32-based M5 Atom Matrix in the main bedroom, which displays it using a 5×5 RGB matrix, as demonstrated after the break. Both ESPs run ESPHome, so programming is as easy as giving it a YAML config file. [WJCarpenter] tested a few different light sensors, until he found the TSL2591, which is sensitive to the right wavelengths and has enough dynamic range for watching a pilot light.

This might not be a complicated hack, but we do not doubt that it reduces frustration a bit on those fateful mornings. Be sure to check out the Water Watcher project page, it’s an entertaining read! Continue reading “Keeping An Eye On The Water Heater Pilot Light”

Fail Of The Week: Solid State Relay Fails Spectacularly

A lot of times these days, it seems like we hackers are a little like kids in a candy store. With so many cool devices available for pennies at the click of a mouse, it’s temptingly easy to order first and ask questions about quality later. Most of the time that works out just fine, with the main risk of sourcing a dodgy component being a ruined afternoon of hacking when a part fails.

The stakes are much higher when you’re connecting your project to the house mains, though, as [Mattias Wandel] recently learned when the solid-state relay controlling his water heater failed, with nearly tragic results. With aplomb that defies the fact that he just discovered that he nearly burned his house down, [Mattias] tours the scene of the crime and delivers a postmortem of the victim, a Fotek SSR-25DA. It appears that he mounted it well and gave it a decent heatsink, but the thing immolated itself just the same. The only remnant of the relay’s PCB left intact was the triac mounted to the rear plate. [Mattias] suspects the PCB traces heated up when he returned from vacation and the water heater it was controlling came on; with a tank full of cold water, both elements were needed and enough current was drawn to melt the solder build-up on the high-voltage traces. With the solder gone, the traces cooked off, and the rest is history. It’s a scary scenario that’s worth looking at if you’ve got any SSRs controlling loads anywhere near their rated limit.

The morals of the story: buy quality components and test them if possible; when in doubt, derate; and make sure a flaming component can’t light anything else on fire. And you’ll want to review the basics of fire protection while you’re at it.

Continue reading “Fail Of The Week: Solid State Relay Fails Spectacularly”

Hippie-Redneck Solar-Heated Swimming Pool Slash Hot Tub

In need of a jacuzzi to complete your backyard but just don’t have the cash? Need a swimming pool for the little ones but tired of the cheap plastic ones popping and leaking all over the place? Look no further than [inexplorata]’s self-explanatory “Hippie-Redneck Solar-Heated Kiddo Swimmin’ Pool And Hot Tub“.

The pool uses a six-foot-diameter metal stock tank, provided by a neighbor. After some liberal use of JB Weld, the tank functions as a makeshift pool on the cheap, but the magic doesn’t end there. [inexplorata] found a solar thermal water heater that someone was getting rid of and snagged it to heat up the water, which is almost a necessity for most parts of the Northern Hemisphere right now.

A sump pump in a bucket handles water circulation, and [inexplorata] points out that the single water heater is more than enough to keep the water nice and warm (“hot enough to poach a rhino” is the scientific term used on the project page) so if you’ve got the means, this might be a welcome addition to the backyard! The build was posted on Reddit, the users of which had some helpful suggestions for improving the pool if you want to tackle this yourself. If you don’t have a solar thermal water heater, you could always make one of those too.