Passive Solar Lath House

My question is regarding lath houses and their ability to trap passive solar radiant heat inside the structure.

We’re working on establishing a permaculture education center in Eastern China and are retrofitting a northeastern style house and courtyard accompanying the land. At the southern side of the house, a polytunnel originally connected the kitchen with the toilet, but it collapsed several times under light snow fall and hasn't been rebuilt in several years.

A large hill blocks out winter afternoon sun, but the greenhouse apparently had decent heat gain throughout the winter when it was up, supporting a few tropical perennials. I’ve been in many polytunnels here throughout the winter months and they frequently reach summer temperatures as the coldest days are usually the sunniest.

The polytunnel isn’t something I’m interested in, creating a lot of plastic waste, requiring frequent maintenance and adjustments for airflow and temperature control, etc etc. I want the microclimate to be self maintaining at about +5 degrees in the winter and to provide substantial shading under the very hot direct subtropical sun throughout the summer.

I’m thinking to build a bamboo lath house with a few square meters of PMMA directly facing the late December 11am sun, hopefully allowing a substantial amount of solar gain throughout the typically sunny winter months. Thermal mass would be oversized raised beds which would filter gray water from the kitchen and shower, along with several rain barrels, a few boulders and a small pond.

The question is, will the lath house, with bamboo slats covering perhaps half the surface area, be able to keep in enough radiant heat to keep temperatures a few degrees above the ambient temp throughout the day and into the night? The area isn’t particularly windy so I imagine this could provide at least some protection, I remember I’ve heard lath houses stave off frosts by having the cold air slide down around the structure rather than entering directly inside. I’m also not sure how this would work with the summer heat, but I would plan on growing a few vine crops on trellis over the PMMA. Has anyone seen or heard of passive solar lath houses before?

Thanks for your time!
Thomas

10 years on, how did this project work out?

It looks like you didn't get much feedback, but perhaps you could fill us in if it worked out, or didn't.

It turned out the topography to the south and west shaded the area too much to make this idea viable. This was back before we used satellite topography and software for our passive solar designs. With only 2-3 hours of sunshine a day it just wasn’t possible to grow through the winter. We later caved and setup a poly tunnel on the ridge for winter growing.

We have since designed and built many of the usual-variety passive solar structures with good success. I do still like the idea of lath houses for establishing microclimates but haven’t built one yet.

How has the maintenance of the poly tunnel gone?

This is interesting.
With such tight spacing between supports, narrower pieces of glazing could be used.
This might materials like fish skin viable.

William Bronson wrote:This is interesting.
With such tight spacing between supports, narrower pieces of glazing could be used.
This might materials like fish skin viable.

Yes, I hadn't come across lath houses before and had to look them up. There doesn't seem to be much discussion online that I can find. They seem to be a variant of a shade house - forming shelter from sun in summer and wind in winter, so creating a sheltered environment from the extremes.
I tend to think they'd be more useful against summer heat than winter cold without some glazing though.

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They certainly seem to be durable though - there's one in San Diego that was made in 1915 and still appears to be protecting it's plants!

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Thank you for the thoughtful replies!

The lath house idea stemmed from reading a study done on how the San Diego Lath House managed to stave off frosts during some unusually cold winters. I was aiming for something similar in a subtropical climate, using the lath to direct the flow of cold air coming down the hillside and to slightly modify the microclimate. I had seen a number of examples of lath houses in use around China and didn’t realize they were a relatively rare strategy at the time.

In 2014 the site was commandeered by the government under eminent domain to develop an oil pipeline and high speed train line. We used the compensation to continue developing projects on other sites.