Well (as opposed to all the HN posts about Rust and GoLang), this is a topic I actually know a smidgen about while running a solar water pump venture out of East Africa. AMA.
I am somewhat involved in a restoration project of a building in Italy (pet project, not my job, I'm a tech guy).
We are considering installing geothermal power to warm/cool the building. Anything of what you know applies to that?
There is a water canal nearby, and therefore there's a plan B that involves exchanging heat with the water in the canal.
Relevance to original article, for example, are that there are ventures around here that focus on water suction, but their scope is practically limited to surface water. We’ve focused exclusively on submersible pumps so that farmers with wells can tap their groundwater for agriculture with us.
Finally, what problem are you solving for?
Solar water pump (SWP) systems are expensive to our target market of smallhold farmers when purchased with up-front cash. Since a SWP is an income-generating appliance for its user (apply water toward grow crops -> sell crops -> $$) we focus on how the farmer can sustainably make a down-payment and pay off the SWP on a rent-to-own basis. The market and industry space is widely distributed, so we target equipping distributors to accomplish the above with farmers in their respective geographies.
>what's the technical setup? > the panel Typically 120-200W collapsible solar panels that the farmer deploys daily.
> controller Our IoT controller that collects local environmental & usage data that equips distributors to monitor their productivity (and so their anticipated loan performance). > and pump. DC-submersible, capable of delivering shallow groundwater accumulated over recent rainy seasons. (Power level matches the panels minus losses). Difficult to go into more detail than that without exposing more about our specific go-to-market strategy rather than anything that helps bring more farmers and distributors to the table. At the end of the day, pump models & panel sizes run the gamut in any given country's market - we help distributors select among these in their local market rather than exporting one SKU to everybody.
>What's the wattage and parts etc. As above, with hosing & cabling sufficient for the groundwater depths involved. Accessories beyond that like sprinklers and a bag for carrying are generally appreciated by farmers.
>What's the final cost? We have offerings between $600-$1300 paid out over a year. Of course a distributor can choose whatever payout plan they feel their local farmer market will bear.
That said, the case for storing energy during dark hours can still be a good one, provided 1-4 are satisfied/mitigated. Early morning hours are an excellent interval to irrigate over, and the solar irradiance at those hours is often still too low to utilize the pump’s full delivery & depth (head) capability.