Posts Tagged ‘contracting’
Using the ground for Geothermal in Florida
When the ground gets used for storing and discharging temperature, the whole energy transfer becomes pretty complex. Below is a great schematic I found on a NASA website describing global warming. Among other things, this illustration shows all the energy transfers that effect the upper surface of the ground. With respect to geothermal air conditioning, we would add to this energy diagram with our piping system of course. [caption id="attachment_150" align="aligncenter" width="478" caption="Energy Transfer at earth's surface (from NASA)"][/caption] This illustration was produced to help explain global warming. Notice anything strange? As a mechanical engineer, we were taught in engineering school to define boundaries of whatever we are studying and include all energy within the boundary and crossing the boundary. So I am calling attention to energy transfer from the center of the earth the the earth's crust. It is not represented in the above illustration. I have not found any information on this subject that a non-astro-geophysicist type like me could understand, but that doesn't mean it isn't important. If any readers out there can enlighten us on the core of the earth's exact contribution to soil temperatures, please do. Anyway, ...
How Geothermal is Different in Florida
As geothermal air conditioning and heating gains popularity; a large and sometimes confusing amount of data is surfacing regarding geothermal techniques. I get asked a fair amount about what types of geothermal systems and I also hear a few reports of geothermal-gone-bad. To help clarify why Florida has a unique geothermal system compared to other parts of the US-- let's start above ground. Climate-wise, Florida has far more cooling demand than heating demand. This has a double impact. First, geothermal systems during a Florida summer pump more heat into the ground than they take out in winter (for space-heating purposes). This tends to make geothermal systems relying on surface temperatures unstable through time. Second, the winters in Florida are short and mild to the point that they are not able to "recharge" the ground temperatures. This is not to say that there aren't a few buildings in Florida with relatively matched heating and cooling loads though. I am referring here to buildings that use a lot of hot water for industrial processes or domestic purposes (such as factories, heavily used kitchens, and laundrymats). Cases like this warrant special consideration. Now, let's look below ground and see what else makes Florida different geothermally. The second thing that makes Florida unique geo-thermally ...
programmable thermostats
[caption id="attachment_31" align="alignright" width="112" caption="Guy Van Meulebrouck"][/caption] I just found a 2010 survey from Lawrence Berkely National Laboratories regarding how programmable thermostats actually wind up being used by occupants. The study reported a survey of 81 residential thermostats and found the following: • 45% were in hold • 30% were programmed • 10% were manual thermostats (not programmable) • 5% were off • 10% operational status was not visible in the picture. The complications involved in each particular thermostat's programming are evident here. I envision a thermostat in the future that uses user friendly computer software and then transfers information to the thermostat via a USB memory stick. The same innovation would be welcome for sprinkler timers too! I used to specify Honeywell T7350's as a general practice. These which are challenging to program correctly due to the immense features. It took me two tries to get my own T7350 programmed right. The local Honeywell representative assured me that he pre-programmed the thermostats himself before he delivered them to jobsites. Great idea. He welcomed me adding information on my drawings as to specific settings that were needed for the building. Guy Van Meulebrouck PEconsulting engineerguy@guyvanmconsulting.com10947 ...
