#solarventi

En Solarventi är en låda som suger in luft med en solcellsdriven fläkt. Luften värms och avfuktas inne i lådan och förs sedan in i huset/rummet på andra sidan väggen av samma fläkt. På insidan av huset får du då varmare luft än ute och dessutom en torrare luft. På det stora hela så pressas även den fuktigare luften inne i huset ut via sin ventilation. Jag har utvärderat funktionen på två…

In today’s world, most people have invested in one form of an air conditioner or another. We have either reverse cycle, portable, ducted or split system air conditioners in our homes. They keep us cool in the extreme summer heat without fail. However, have you ever sat back and looked at the costs of running an air conditioner? When compared to the common household fan the amount of electricity required to run an air conditioner is enormous. The difference in weather conditions from year to year will also greatly affect the costs.

What happens when the peak demand is soaring, the ability of the supply grid to support that supply becomes overwhelming, and we get blackouts because the grids can’t support the demand for extra power. The grid goes into self-protection mode by limiting the amount of power that it can transmit, resulting in entire geographical zones being shut down.

 Ventilation is essential to a clean and healthy home. Not only does it keep the air clean but it keeps bacteria, air borne virus’s, damp and mould at bay and keeps timber and building structures protected from termites, rust and corrosion.

Energy

When compared to the common household fan the amount of electricity required to run an air conditioner is enormous. Air conditioners literally devour electricity. The energy an average air conditioner uses in on 3 hours is enough to power a fridge for a week. A large electricity bill may affect you in the short term, but high-energy consumption is likely to affect the environment in the long term.

‘Monthly costs assume cooling is used for 4 hours per day.’

Fan (portable or ceiling) 1c approx. $1.60 

Evaporative cooler (portable) 2c approx. $6.50 

Evaporative cooler (ducted) 10c–14c $23–$34 

Reverse cycle air conditioner (window/wall or split system, 1–2 star rating) 33c–35c $42–$47 

Reverse cycle air conditioner (window/wall or split system, 4–6 star rating) 24c–37c $30–$35 

Reverse cycle air conditioning (cooling whole home) 55c–80c $71–$102 

Ducted reverse cycle air conditioning (zoned system—bedrooms and living areas cooled at separate times) 32c–47c $37–$55

Ref* Sustainability Victoria.

External Conditioning

On top of massive energy consumption, the use of many air conditioners can and does affect the local temperature. As the cool air is created inside, intense hot air is pumped outside via the condensers. This creates heat zones, multiply these zones in a city and you have what the science world call an urban heat island. This is the name given to describe the characteristic warmth of both the atmosphere and surfaces in cities (urban areas) compared to their (non-urbanized) surroundings.

Take for example blocks of apartments, office blocks or large commercial buildings, pumping out 40C to 60c per unit to the already hot external air temperature. When you add up a city’s worth of air conditioners, you can understand why it is that cities are hotter than the countryside in summer. This additional heat also creates a microclimate convection system whereby the hot air rises swiftly in pocketed areas, creating many new abnormal localized weather patterns.

Refrigerants

Another environmental concern is the use of refrigerants in air conditioners. Hydro Fluro Carbons (HFCs) such as R410A or R407C are the most commonly used refrigerant type found in domestic air conditioners. While HFCs don’t damage the ozone layer like CFCs do, they are a much more potent greenhouse gas than carbon dioxide, with profound consequences.

Greener alternatives

The latest wave of green alternatives for cooling and heating your house are geothermal pumps, solar ventilation or solar fans, and HRV (heat recovery ventilation) systems.

Ground cooling/heating systems, solar (Solarventi) or geothermal pumps can provide adequate comfortable natural air conditioning to any building. The obvious advantages being initial minimal running costs with minute carbon emissions. The added benefits being that fresh filtered air is ventilating the property thereby creating a fresher cleaner and healthier internal environment.

Solar ventilation systems will run cost free and most are maintenance free.

Electric fans

Fans use a fraction of the power of that of air conditioners, as they only have to rotate blades, but as such they only move the air around - they don’t cool it.

Ceiling fans cool by creating a low-level “wind chill” effect. This windchill effect makes you feel cooler by accelerating the evaporation of moisture on your skin. As long as indoor humidity isn’t stifling, they can be quite effective.

Insulation

Insulation, in its many forms, helps stop the transfer of heat from one place to another. A good example of this is the insulation in the attic. A thick layer of insulation helps to stop heat flow from the house to the attic during the winter. In the summer, that same insulation helps stop heat transfer.

Tips – if you do feel the need to use your air conditioner

- Keep filters clean. Filters blocked (with dust) make the machine work harder and use more electricity. - Each degree you are able to raise the thermostat, you will save 3–5% on air conditioning costs. - Keep the air in the room moving – use a fan. A little breeze will make it feel even cooler. - Using a timer to automatically switch air conditioners on and off. If your model doesn’t have a timer function, use a separate plug timer between the air conditioner and the plug socket. - Reduce heat gain by pulling drapes or shades, and use shelters to prevent direct sunlight from streaming in through windows on the south and west-facing sides of the house. Overhangs, patio overheads, latticework, awnings work well. - Always keep all doors and windows closed when operating an air conditioner. - Don’t cool unoccupied rooms (but don’t shut off too many vents either, or it will put pressure on the system). - Install inexpensive heat-reflecting film on windows that face the sun. This will keep the house cooler and reduce glare and ultraviolet rays that damage furniture and floors. - Hire a professional technician to inspect, clean, and tune your system every 2-3 years. - One of the most important principles of an energy-efficient home is to keep the house or building air sealed. Air sealing prevents the flow of heat from outside to inside and outside. Weather-strip all windows and doorways.

The importance of drying in damp houses as a part of the daily health is essential.  In some cases, changes in the weather can affect drying but, for now, let’s just concentrate on drying.

Drying simply means removing dampness remaining on the absorbent  parts of the house structure and soil as a result of flooding, natural seepage or pipe leaks.  This is accomplished after one of two ways of removing the  physical liquid.  Physical removal of liquids may be as simple as opening a hole in the brickwork at the lowest point of the subfloor area that will allow the flowing liquid to drain due to gravity.  Or, it may involve using a pit or sump pump in closed or encased subfloor areas to mechanically draw that liquid out to a more suitable drain area. Drying then begins with either two ways slow positive input of dehumidified warm air in combination with a negative balanced airflow to keeping motional cross balance. Two is to swiftly draw air at quantities using negative pressure only using means such as a large fan from the lesser part of the building drawing warmer dryer air in from the  greater side of the building. Both methods creating the more commonly known method of evaporation.  Evaporation of liquid is usually enhanced through the use of heat and the movement of air over the area. In today's Australian climate, cross ventilation is rarely suitable due to boundary enclosures, fences, close buildings, differential wind direction and incorrect vent placing.

At first, drying by evaporation would seem very simple.  The evaporation of liquids, after all, is nothing spectacular.  It’s a process we see every day.  It rains, the sidewalk gets wet.  The rain stops and the sun comes out and the water on the sidewalk evaporates and is gone.  Job done, however take a deeper look, and think where all that water has dissipated to? It also reveals that there is more to evaporation than one might think.  The belief is that the  rate of evaporation depends on temperature only!  The higher the temperature, the faster evaporation takes place!  Well, actually, yes but in fact not completely correct!  The rate of evaporation is actually driven by the relative humidity to a greater degree and air movement than by temperature.  As the temperature of air is increased, it can absorb more liquid and, therefore, the relative humidity is decreased. The greater the air movement the greater the displacement of lower humid air.  Lower relative humidity promotes faster drying.  The following chart and graph which both show essentially the same data are very interesting.

As temperature is increased, the amount of water required to saturate a specific volume of air increases.

This graph shows that as the temperature of air increases, the amount of water required to saturate it increases dramatically. A few degrees of increase in temperature has an increasingly large effect on the saturation point. So, take for example a subfloor area at a temperature of 10C, with 100 RH, this would hold 7.8 grams of water vapour per Kilogram g/Kg. -  Now, introduce airflow continually at only 20C, and 50% RH - not much, but this will have the capability to hold twice the what is present specs (20C -15 g/Kg). Take it another step, continuously drawing this 20C air which holds double the g/Kg capacity through your subfloor area and then displaces it externally will not only change the air temps and humidity but will draw the dampness (moisture) out of surrounding structures (timber and brickwork). Doing this process on a daily basis and allowing stagnation at night allows building structures to become dryer, subfloors temperatures raise by a couple of degrees and humidity levels to drop dramatically.

Air at 100% humidity is saturated with water.  If a volume of air saturated with water is heated, the level of saturation is decreased and the air requires additional moisture to again become saturated. Air that is saturated with water is at a relative humidity of 100%.  Air that contains only 50% of the water required to be fully saturated is at a relative humidity of 50%.  Similarly, if the temperature of a volume of air that is saturated is reduced, water comes out of the air as a fog or water droplets.  The “dew point” is the temperature at which air becomes fully saturated.  In weather terms, this is when it rains. In thermal bridging of surfaces at a lower temperature, this is when you see condensate.

Relative humidity in percent is the total water required for a volume of air divided by the amount of water that would be required to be totally saturate that volume of air.  In drying, it is important to understand the role of both temperature and humidity and how they are related.  Next consider the complete implication that by drying and slightly raising the temperature of what is normally the coldest and wettest part of the house, would have on a daily basis.    

Why do you feel colder when it’s humid? 

The Question: “Why do you feel colder when the air is humid? I understand why higher humidity, which suppresses evaporation cooling, makes you feel warmer at normal temperatures. But people keep telling me opposite is true when it gets near freezing or below. I am not buying this. All other things being equal (same wind, no rain, dry clothes, etc.) I suspect moisture in the air will always make one feel warmer, even at 20 degrees. Help me settle this argument.”

Limiting Case Experimental Answer

In science, the ultimate arbitrator for answering questions is experiment rather than theoretical arguments. Physicists also often use the limiting case to gain insight into a particular situation. The limiting case of high humidity is 100% humidity, which means its raining. Anyone who has ever been caught in a cold rain while wearing inadequate clothing knows that 100% humidity during cool weather makes us feel much colder than if it were dry at the same temperature.   This experiment strongly suggests, but does not prove, that high humidity (dampness) during cold weather makes us feel even colder. The same mechanisms that make people feel colder during a cold rain contribute to making cold damp weather feel colder.

Why Humidity Makes a Hot Day Feel Hotter

Moisture in the air contributes to your body’s cooling processes.

It helps to first understand why high humidity on a hot day makes the perceived temperature higher. Sweating is a cooling mechanism. When the humidity is low, sweat evaporates easily. Evaporation requires thermal (heat) energy, so evaporation is a cooling process. When our sweat evaporates it cools our bodies. On a hot humid day, sweat does not evaporate as easily, so the body’s cooling mechanism does not work as well. The limited evaporation in humid conditions is not enough to cool the body.

When it is cool and humid, the body does not need a cooling mechanism, so the body sweats less. The high humidity does not therefore limit evaporation to keep the body warm as it does on a hot humid day. Additionally, on a cool dry day, the low humidity does not increase the body’s cooling rate as it does on a hot dry day because most people do not sweat significantly when it is cool.

Therefore the mechanism that causes a humidity to make a hot day feel hotter does not apply in cool weather.

Why Dampness Makes a Cool Day Feel Colder

On a cold rainy day the falling rain soaks our clothing to make us feel colder. On a cool damp day, it is less obvious, but our clothing can also absorb some moisture from either the damp air or our bodies. Whether it is raining or simply damp, wet clothing does not keep us as warm as dry clothing for a few reasons.

Even if it is humid, some of the moisture in our clothing can evaporate. Evaporation still serves as a cooling mechanism. This effect is usually small.

Our clothing keeps us warm on cool days by trapping air between our bodies and clothing. The clothing, and layer of trapped air, prevents our bodies from losing heat by convection currents, which transfer heat by circulating air like a cool breeze on a hot day. Air trapped by clothing cannot easily circulate to transfer heat and cool our bodies. The body must first warm this layer of trapped air to keep us feeling warm.

Cloud cover on stormy days reduce the warmth we feel from the sun. 

On a very cool damp day, however, this layer of trapped air contains water molecules. If it is damp, our clothing is also likely to contain some water molecules. It takes more heat energy to warm water than air. In physics parlance, water has a higher specific heat capacity than air. If the layer of air next to the skin is damp, it therefore takes more of the body’s heat energy to warm it. Hence the perceived temperature is cooler.

Finally, liquid water conducts heat better than air, although humid air does not conduct heat better than dry air. If the dampness causes some liquid water to form on our skin or in our clothing, the water can conduct heat away from our bodies.

Another effect contributes to the cooler feeling outdoors on a damp day versus a dry day: A damp day is more likely to be overcast than a dry day. On a dry sunny day, the body is warmed by radiant heating from the Sun. A damp day is more likely to be overcast and therefore have less radiant solar heating. It will therefore feel cooler.

For a variety of reasons dampness can make a cool day feel even cooler. www.solarventi.com.au

For the 10-year period, 1998-2007, Australia had excess winter deaths of 6,779 per yr out of a total of 131,613 deaths per yr (avg.) This works out to 5.2% of all deaths per yr (on avg). Cold homes have been linked to poor health by many studies; the extreme example of this is the phenomenon of excess winter deaths. Some studies link particular health outcomes with temperature; one important study shows a minimal in cardiovascular mortality at a daily mean temperature of about 20 degrees C. 

 Research also indicates that heart attacks and strokes in particular are more prevalent during winter as opposed to during the summer. These health outcomes are strongly associated with poverty (Asplund 2003) but Wilkinson et al (2001) found that cold related mortality was greatest in the coldest homes. Healy found higher ratios of winter deaths to summer deaths in warmer climates than those of the coldest EU-14 countries (the highest was Portugal with 28% more deaths in winter months than summer, UK; 18%, Mean; 16%). Other health outcomes linked with cold homes includes the findings of Strusberg indicating that rheumatic pain is linked to climatic conditions, specifically humidity and temperature. (Strusberg and others 2002). Even some relatively warm homes can “feel cold” to some occupants. This reflects the fact that many factors affect an occupant’s thermal sensation or “thermal comfort”. Fanger (1970) states; “thermal comfort is that condition of mind that expresses satisfaction with the thermal environment”. However, he also found that thermal comfort is dependent on six main environmental variables, air temperature, relative humidity, radiant temperature, air speed, clothing level and metabolic rate (activity level). If the home is both cold and has high moisture levels a consequence can be mould and damp, the health effects of mould and damp are significant. 

 Respiratory symptoms were found to be linked in different ways to different housing factors for children and for seniors. Draughty homes are were linked to fewer symptoms while poor heating systems were related with increased prevalence of respiratory problems for children. For seniors, having problems with cold temperatures in winter and being dissatisfied with the homes insulation were both associated with increased prevalence of respiratory symptoms. Cardio-vascular problems were strongly linked to age, weight and gender, but after compensating for these, only Mould_Score was found to be a factor from all the housing factors considered (see mould chapter elsewhere in this book for more details). Arthritic problems were very strongly linked to age; however within the senior age grouping, “problems with cold temperatures in winter” were also significantly associated with arthritic problems. It is important to note that arthrosis, degeneration essentially due to age, was classified in the same category as arthritis, so this may have led to a confusing picture resulting from the analysis.

Ref:- http://discovery.ucl.ac.uk/16832/1/16832.pdf http://joannenova.com.au/2011/11/7000-excess-winter-deaths-in-australia-and-1500-in-new-zealand-each-year/ https://books.google.com.au/books?id=BD59AgAAQBAJ&pg=PA143&lpg=PA143&dq=thermal+comfort++arthritis+humidity&source=bl&ots=FlQZsG_oJl&sig=1bL3W8jLy9DxPX4X_Kd35zMh8SI&hl=en&sa=X&ved=0ahUKEwj2pe3LkJ_NAhWJKZQKHV1sBwsQ6AEITjAH#v=onepage&q=thermal%20comfort%20%20arthritis%20humidity&f=false

Recoup up to $20k, then have no annual running costs. Massive ROI.

If you have a small business you will be able to fully tax deduct your purchase if it’s under $20,000. Ask your accountant now. You can claim an instant tax deduction on items that are used to run your business up to $20k for each item. So it’s the perfect time to get that ventilation system to cool you and the staff down, your summer overheating in the warehouse or offices will be history with our powerful solar roof fans. No more stuffy air conditioning.