Traditionally underground caves or rooms (root cellars) have been used to preserve food & keep cool also in our living spaces, using the fact that about a 1m underground the temperature is usually constant (so cooler in summer & warmer in winter)
But there are other cooling effects which are exploited in refrigeration technologies, notably the effect of evaporation & pressure changes in fluids.
What happens to every drop of water that evaporates from your water tumbler? How much energy could that drop contain? Principles of Refrigeration Instructions on how to build and use an Evaporative Cooler Fridge, Zeer Pots and Radiant Fridges (solar ovens used for cooling, or even making ice, at night). Prehistoric refrigerator called a Zeer Pot Fridge. Cool your food or drinks with no electric needed. This DIY project uses a red clay pot and sand to cool the contents inside from evaporation. Evaporator coolers work great and they are very easy to make. This Zeer pot might have been what the ancients used to keep their produce fresh in the summer seasons to last longer. I think this could be very handy if we were to loose power..  Detailed information about evaporative cooling and charts on possible temperatures depending on environmental conditions, and on the results of choosing different materials, shapes, sizes... The cool boxMarina and Robert of Dell Artimus Farm take a general electric 1930's refrigerator, strip out the motor and add in .... spring water. Refrigeration without any electricity. Easy peazy. From www.permies.com   With detailed information and building instructions for different types of root cellars, ice houses made with pykrete, and other vegetable storage structures (outdoor barrel storage pit, storage straw mound, etc.). Draft FridgeIn the first part you can see David Holmgren's draft fridge design This is in Temperate Permaculture Strategies - Pt4 Animation of compression refrigeration cycle and air conditioning Heat of vaporization Pressure and boiling point Why is an aerosol can cold? Compression refrigeration loop Condensing and evaporating coolant Window air conditioning unit Compressor, expansion valve, evaporator coil, and condensing coil Parts 2 and 3 include content on active heating, air distribution, air handling units, cooling towers, indoor air quality, chiller operation, ground-source-coupled heat pumps, and economizer cycles Part 2 Part 3 Go to our Natural Building Blog where we answer questions. http://naturalbuildingblog.com Today I want to talk about passive cooling strategies for keeping your home cool in hot climates. This is a very hot climate and yet our earthbag roundhouse is about 15 degrees Fahrenheit cooler inside than out. So 15 degrees Fahrenheit, 8 degrees Celsius temperature difference with no mechanical cooling systems. Passive Solar COOLING - For Hot Humid ClimatesBasic solar science can be used to keep your home cool without electric bills. Zero Energy Design® has been doing it for decades. By Larry Hartweg ZEDmaster@ZeroEnergyDesign.com  Evaporative cooling differs from typical air conditioning systems which use vapor-compression or absorption refrigeration cycles. Evaporative cooling works by employing water's large enthalpy of vaporization. The temperature of dry air can be dropped significantly through the phase transition of liquid water to water vapor (evaporation), which can cool air using much less energy than refrigeration. In extremely dry climates, evaporative cooling of air has the added benefit of conditioning the air with more moisture for the comfort of building occupants. Unlike closed-cycle refrigeration, evaporative cooling requires a water source, and must continually consume water to operate.  Information about stack ventilation, Bernoulli's principle and designing for both in buildings (to increase cooling by air flow), and also about solar chimneys. A windcatcher is a traditional Persian architectural element to create natural ventilation in buildings. The windcatcher can function in three ways: directing airflow downward using direct wind entry, directing airflow upwards using a wind-assisted temperature gradient, or directing airflow upwards using a solar-assisted temperature gradient. | See also Solar Air Heating (information about solar chimneys, which are mainly used to create airflow & cool buildings, and some science that can be used minimize solar heat collection and maximize air flows). Watering (as many cooling systems use water, which specially needs to be harvested & stored efficiently in hot & dry climates). |
