I've seen a 1 1/2 story greenhouse, the backside full height, with a tromb wall of black 55 gallon barrels, filled with water and sealed, on the ground floor beneath many large drying racks, built from small wood stock and plastic screen fabric. The greenhouse was the front of the ground level and had a lower ceiling of glass panels, slanted up and back to direct the naturally rising hot air up and through the screened drying racks. There were adjustable vents to control the airflow and temperature. This was many years ago and I'm sure I'm not remembering some of the details, but most any greenhouse that's too hot mid to late summer to grow crops could be utilized as a dry house for dehydrating a gardens bounty.