Wednesday, November 12, 2014

Computer Time Jargon: Unix Epoch, UTC, GMT

Computers represent TIME with many words that have similar meaning.  It creates a wall of words to climb before understanding.

UNIX Time = UNIX Epoch Time = Epoch Time = POSIX Time 

  • the number of seconds since 1/1/1970, the year Unix was born 
    • Unix computers count the time in seconds since its official "birthday," -- called "epoch" in computing terms -- which is Jan. 1, 1970.  
    • Unix engineers needed to set a uniform date for the start of computing time, and New Year's Day, 1970, the same year they started developing it, seemed most convenient.
    • Linux follows the same tradition. [Reference]
    • Years < 1970 are negative
  • Timezone it represents ALWAYS equals UTC = Universal Time = GMT [Reference]
  • More Jargon:
    • Epoch = reference point from which time is measured
    • POSIX = Portable Operating System Interface.  These are the standards that Unix and Linux were built upon.
UTC = Coordinated Universal Time = GMT = Greenwich Mean Time

  • Timezones around the world are expressed as positive or negative offsets from UTC.


#Wall.Of.Words #computing

Friday, October 17, 2014

Checkboxes: Check All or None on Webpage

GOAL:  Repeat checkbox multi-select similar to Google Docs and Gmail for editing multiple items in JavaScript / jQuery.

$('input:checkbox').attr('checked', true);
$('input:checkbox').attr('checked', false);

Thursday, September 11, 2014

"Save as Image" PNG/JPEG in Keynote [for Mac]

GOAL:  Save image in Keynote as a PNG, JPEG, PDF, or TIFF.


1.  Copy Image in Keynote

2.  Open Preview App

3.  File > New from Clipboard

4.  Desired image should now be opened

5.  File > Save... > Choose Format > OK

Crop Image in Mac Keynote

PROBLEM:  Cannot find "Crop" or crop icon anywhere in Keynote.


1.  Click Image

2.  Format > Image > Edit Mask

3.  Crop button now shown.  Adjust to desired size.

4.  Done


Tuesday, July 15, 2014

iframe Part of a Webpage

Scrape a part of a webpage onto another.

iframe + disable scroll + adjust margins + set width/height

<iframe src="" scrolling="no" style="height: 280px; width: 619px; margin-top: -220px; margin-left: -230px; border: 0px none;"></iframe>

Scraped Example of World Population Website

This will work as long as the webpage doesn't re-arrange content.  Debated between an iframe or jquery to scrape a certain element.  Accessing with jquery ended in permission error:

Tuesday, June 24, 2014

Mac App Can't Be Opened Because Unidentified Developer [Fix]

Can't be opened because it is from an unidentified developer (often from a newly downloaded app from the internet).  Only OK shows in the pop-up and there is no way to Open.


1.  Applications folder

2.  Right Click on App

3.  Open

4.  Pop-up now shows "Open" button.  Click "Open" to use the app.

Friday, May 30, 2014

Revit Origin

GOAL: find the origin (0,0,0) of a Revit 3D Building Model

  1. Double Click "Level 1"
  2. "View" Tab
  3. Visibility / Graphics
  4. + Site
  5. Check "Project Base Point" & Survey Point
  6. Apply
  7. OK

Origin will now show in red.

Specific to Revit 2012.  No guarantees past this.

Wednesday, May 28, 2014

Server Jargon: Memory vs. Storage

The memory and storage are separate pieces of hardware from the processor (described here) also on the motherboard of a computer or server.

Memory = RAM = Random Access Memory
  • Short Term Memory
  • Physically: a thin metal & plastic board

Storage = Disk Space = Hard Drive (HD) = Solid State Drive (SSD)
  • Long Term Memory
  • Physically: a small metal box

WOW.  If you're a server beginner, this is another Wall Of Words you have to climb.
I'm not a computer engineer, just a software developer.  This is my understanding as of May 2014.


Server Jargon: Processor vs. Core vs. Thread

A thread is inside of a core which is inside a processor which sits in a socket on a motherboard of a computer or server.  WOW.  If you're a server beginner, this is one of the Wall Of Words you have to climb.

Processor = CPU = Central Processing Unit
  • Physically:  a tiny metal board with circuits and nano-sized wiring that sits inside of a "socket" on the "motherboard".
    • Socket = the slot the processor sits in on the "motherboard"
    • Motherboard = PCB = Printed Circuit Board for a computer/server
      • 2014 Support:  only 2 sockets / slots are in a motherboard
  • Sized by:  
    • Clock Speed = # calculations in 1 second before degrading (measured in 1million+ cycles/second, MHz or GHz)

Core = a processor inside of a processor
  • Physically: a small black box inside the processor
  • 2014 Support:  2-4 cores can fit inside a processor

Thread = a process = 1 terminal command
  • Physically:  No, thread's don't exist physically.  This is an abstracted OperatingSystem / Software concept.  Certain software languages can only run 1 thread at a time.
  • 2014 Support:  2 threads can run inside a core

I'm not a computer engineer, just a software developer.  This is my understanding as of May 2014.


Thursday, May 22, 2014

Reduce File Size of Image

  2. Open image from computer > Browse for image
  3. File > Save...
  4. Format:  JPEG
  5. Adjust Quality dial & see resulting Size (KB) at bottom
    6.  OK
    7.  Choose where you want the image downloaded to

Free Online Alternative to Photoshop

Pixlr is a free, online, web app alternative to Adobe Photoshop...

It can perform many of the basic functions of Photoshop such as:
  • resizing images
  • setting a transparent background
  • deleting chunks of the image with magic wand
  • converting to JPEG, PNG, BMP, TIFF
  • adjusting the color or grayscale, etc.  
It's all FREE and doesn't require any installs.

Friday, May 2, 2014

Bootstrap #id href Link Covered by Nav Bar [Fixed]

< h1 id="output" style="padding-top:40px; margin-top:-40px;">

this does not create extra space in content & href to #output now jumps down to this anchor without the top nav bar (default in twitter bootstrap) covering the title up.  no change needed for the href="#output" tag at top.



Thursday, May 1, 2014

OpenSSL Bug Fix for Ubuntu Linux 12.04 by Bitnami

The OpenSSL Heartbleed Bug affected the majority of the internet in early April 2013.  If you haven't patched your ubuntu server yet...

built on: Tue Jun  4 07:26:06 UTC 2013
(or anything earlier than Apr 7 2014 is vulnerable to the OpenSSL Bug)
OpenSSL 1.0.1 14 Mar 2012 does not matter [reference], only the "built on" date.

built on: Mon Apr  7 20:33:29 UTC 2014

sudo apt-get update 
sudo apt-get upgrade
(note: upgrade does not change your ubuntu version)

1. wget 
2. chmod +x ./

3. sudo ./ --mode text


Bitnami creates custom builds of Ubuntu to make the setup easier for developers.  

Disk Space Tool for Ubuntu Linux Server

Find out the breakdown of which files/folders are taking up the most room on your computer / server through command line / terminal.
sudo apt-get install gt5

from the directory you want to analyze:

Ctrl + Z

Ubuntu Linux 12.04


Forward Penn State Email to Gmail

  1. Change your forwarding address (here)
  2. Sign In 
  3. Change

Friday, April 18, 2014

Shortcut Top/Bottom of Page in Chrome for MacOSX

Top of Page
FN + LEFT arrow 
or CMD + UP arrow

Bottom of Page
FN + RIGHT arrow 
or CMD + DOWN arrow

Chrome Web Browser on MacBook OSX
Small Keyboard without right Number Keypad

Wednesday, April 16, 2014

Google Maps Autocomplete

As a user types in an address, Google Maps attempts to auto-complete so the user can see all locations in the world that match the entered address.  It ultimately saves the user time so they only have to enter the start of the address.

All JavaScript & HTML in one file here:


Live Web App:
Code here


Thursday, April 10, 2014

Fix "Cannot find module OpenStudio" for Node.js Bindings on Ubuntu Linux

ERROR: Cannot find module 'OpenStudio'

PROBLEM: Your JavaScript cannot find where the OpenStudio software libraries are.  


1. Login as user & add to $PATH
export NODE_PATH=/usr/local/lib/openstudio/node
sudo -s 
sudo echo 'export NODE_PATH=/usr/local/lib/openstudio/node' >> /etc/profile 
sudo echo 'export PATH=$PATH:$NODE_PATH' >> /etc/profile
2. Login as root & add to $PATH
sudo -i 
sudo echo 'export NODE_PATH=/usr/local/lib/openstudio/node' >> /etc/environment
sudo echo 'export PATH=$PATH:$NODE_PATH' >> /etc/environment

echo $PATH

/usr/local/lib/openstudio/node must show up

POST SPECIFIC TO : Linux Ubuntu 12.04
Jason Turner, Empty Crate

    throw err;
Error: Cannot find module 'OpenStudio'
    at Function.Module._resolveFilename (module.js:338:15)
    at Function.Module._load (module.js:280:25)
    at Module.require (module.js:364:17)
    at require (module.js:380:17)
    at Object. (/home/ubuntu/
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Function.Module.runMain (module.js:497:10)

Friday, March 14, 2014

Trigger Script Every Minute/Day/Week with Crontab [Linux Ubuntu]

GOAL:  Trigger a script every 15 minutes.

Cron = job scheduler in unix-type operating systems
Crontab = Cron Table file that configures shell commands to run on some schedule

STEPS to add script

1.  Write & Save a series of linux shell/bash commands to


*PATHS MUST BE ABSOLUTE, (from root, i.e. /home/user/*
Relative Paths Will Not Work (i.e. echo "hi" > test.txt;).  Must be echo "hi" > /home/user/test.txt;

2.  Open Cron

crontab -e

2.  Select 2 for nano (easiest linux file editor)

3.  Add to bottom of file:

#min hour day month weekday command
*/1   *    *    *    *      <command>
#Run Every 15 minutes
#min hour day month weekday command
*/15   *    *    *    *     /home/user/

*preceding "sh" is not needed before the script path for cron*

STEPS to check cron status/error/log

1.  Check if cron is running

sudo status cron
2.  Open the system log file (for ubuntu)

nano /etc/rsyslog.d/50-default.conf

3.  Find the line that starts with: #cron.*  Uncomment that line to be:


4.  Save the file (Ctrl + Z)

5.  Restart rsyslog

sudo service rsyslog restart

6.  Check cron log file

cat /var/log/cron.log

Also possible to see cron jobs with grep CRON /var/log/syslog
This didn't work for me for Ubuntu 12.04, which is why I wrote this post.


Go to End of File [Linux Nano]

Control + w + v

Jumps cursor to end of open file in terminal

Linux Flavor & Version

Find Linux Flavor (Redhat, Ubuntu, etc) & Version from Terminal...

cat /etc/*-release


Thursday, March 13, 2014

"this" in JavaScript

"this" in JavaScript = a referral to the parent object

adding & removing "this" was the easiest way for me to understand

function OpenStudioModel(buildingData, runmanager) {
  this.model = new openstudio.model.Model();
  this.runManager = runmanager;

"this" is a replacement of OpenStudioModel function
"this" is the current instance of OpenStudioModel
"this" is adding functionality to OpenStudioModel function
"this" is short hand for OpenStudioModel.model & OpenStudioModel.runManager

CodeSchool Definition of "this":  this keyword will automatically refer to the new instance of the class that is being made

Find Automated Logic WebCTRL Point Data for Web Services

Automated Logic (ALC) WebCTRL = controls software for buildings

to find Automated Logic’s WebCTRL point data to connect to Web Services

1.  Login to WebCTRL Website IP (must be using Internet Explorer web browser)

2.  GEO (bottom left corner)

3.  Click on one of the black icons under floor

4.  Points for Web Services = Any Yellow Point.  To see information behind the yellow points:
    Alt + Left Click on a point
    Note:  Right clicking does not work (screenshot below).  Global Modify shows up but is un-clickable.   

4.  Show Advanced

5.  Copy Geographic Location & Network Location

6.  Record & Repeat for each point of interest.

PURPOSE:  To connect a building's ALC WebCTRL to Lucid's Building Operating System, which can integrate each of these points into a more flexible and engaging building data overview.  

These screenshots are only possible because of: 
Payam Delgoshaei, EEB Hub Data Scientist / Controls Engineer

Fix Blank Automated Logic (ALC) WebCTRL Interface in Internet Explorer

Automated Logic (ALC) WebCTRL = controls software for buildings
NOTE:  WebCTRL only works in Internet Explorer web browser.

WebCTRL loads in your browser as a blank white screen, without the typical graphical user interface.  This is an Internet Explorer settings problem - it may be a result of a recent IE update.

SOLUTION = open local intranet security settings in Internet Explorer

1.  Click the Internet Explorer “Gear” (upper right corner), then, "Internet options" :

2.  Click “Security” tab, then, “Local Intranet”, then the “Sites” button:

3.  Click the “Advanced” button:

4.  Add the site you need (your WebCTRL IP):

You may need to disable requiring “HTTPS”:

5.  Go to WebCTRL login & images should re-appear.

all IE settings credit goes to Corey Wilkinson of PSU AE
Payam Delgoshaei for troubleshooting with WebCTRL

Wednesday, March 12, 2014

Terminal Scroll Page Up in Mac

SHIFT + FN + ArrowUp (or ArrowDown)

To scroll up in mac's terminal without your mouse.
Specifically For:
- Terminal or iTerm
- Mac OS X


Tuesday, March 4, 2014

Search Folder or File in Linux Terminal

GOAL:  Search or find a folder/directory/file in Linux through terminal command line. 

find / -type d -name FOLDER
or   find . -type d | grep FOLDER

find / -type f -name FILE
or  find . -type f | grep FILE

find = app on linux
/ = root folder directory
.  = current directory
-type d = directory/folder
-type f = file

NOTE:  These might take a while to show results.

Saturday, March 1, 2014

Reroute Webpage

GOAL:  Reroute a webpage to another webpage.  To do this, just add the meta tag below inside of the head tags of your webpage.  

<meta http-equiv="Refresh" content="0; url="/>

Replace with the webpage you want to reroute to.

If you're using Apache, save the text above into a file called index.html.  The web server will then reroute users to another website completely. 

Thursday, February 27, 2014

Automated Logic's WebCTRL: Web Services Privileges

Automated Logic (ALC) WebCTRL = controls software for buildings
Web Services = communication between two computers over the internet

STEPS to add web services:

1.  Login to WebCTRL Website IP(must sign is as administrator & use Internet Explorer)
2.  Click on CFG (in bottom left)
3.  Privilege Set
a.  Add
b.  Name:  webservices-privilege
c.  Check:  Access Geographic Locations, Access Network Items, Remote Data Access - SOAP
d.  OK (at top of page)

4.  Operators (aka: Users)
a.  Add
b.  Name:  webservices-user
c.  Check: Force user to change password at login
d.  Select:  Do not use automatic logoff for this operator
e.  Check:  webservices-privilege (bottom of page)
f.  OK (at top of page)

5.  Login to WebCTRL Website IP as webservices-user & set password

PURPOSE:  To connect a building's ALC WebCTRL to Lucid's Building Operating System, which easily visualizes energy consumption for occupants.  These same steps can be given to your building operator as a tutorial to add web services "read-only" functionality to Automated Logic's Web CTRL.

These screenshots are only possible because of: 
Payam Delgoshaei, EEB Hub Data Scientist / Controls Engineer,
Stephen Treado, PSU Architectural Engineering Professor & Advanced Controls Lab Director,
Vladi Shuntrov, Lucid CEO

Monday, February 24, 2014

PHP Error on Live Apache Web Server (Linux)

DO NOT install on live server!
I installed PHP on a working Apache and it shut down our web server 1 hour before a demo.  I definitely learned to NEVER mess with your infrastructure before a demo.  We only got it working 5 minutes before the start of the presentation. 

IF YOU DO INSTALL, Here are Suggestions:

  • PHP may have installed incompletely
  • Delete existing PHP files
  • Look for extra tmp folders & files in apache directories
I unfortunately didn't note everything that we did in our rush to fix before the demo.

Ground Source Heat Pump in Trane Trace

Modeling Building Heating & Cooling System:
Ground Source Heat Pump (GSHP) = Geothermal Heat Pump (Overview at bottom)
with Software:  Trane Trace 700 in 2012


STEP 1: Pick Water Source Heat Pump as the system type. Then click Apply to save your entries.

STEP 2: On the Fans tab, select Hydronic in heat pump fan and enter 0.5 for the static pressure.
Next, describe the cooling and heating plants represented by the GSHP system and backup boiler.

STEP 3: Drag the appropriate icons from the Equipment Category section to define each plant. Rename the cooling plant as Ground Source Heat Pump and the heating plant as Backup boiler.
Note: Do not remove thermal storage from the tree. The water loop is modeled as a special thermal storage type in TRACE 700. Removing the thermal storage eliminates the water loop from the simulation.
Note: A boiler will still need to be input for a GSHP model in TRACE 700. (Refer to the "TRACE Requirement: Cooling Tower and Backup Heat Source" section below.) However, if the water loop is properly sized (input as the thermal storage capacity), the minimum and maximum condenser operating temperatures are correct, and the load profile is realistic, the boiler may not activate.

STEP 4: Select the cooling plant and click the Cooling Equipment tab at the bottom of the Create Plants screen.

STEP 5: Choose the ground-source heat pump that best matches the target performance.
Note: The ability of the heat pump to produce heat is defined within the Heat Recovery section of the Operating Mode table on the Cooling Equipment tab in Create Plants. A value must be entered
for both the Capacity and Energy rate for the Heat recovery operating mode:

STEP 6: Enter the full-load consumption of the primary chilled-water pump which serves the common water loop.
Loop temperature for a ground source heat pump system is typically maintained by the heat pumps attached to the system. As some heat pumps demand cooling and others demand heating, the associated addition of heat to the loop may offset the subtraction of heat from the loop eliminating the need for a cooling tower or backup heating source. However, if the system demands more heating or cooling capacity than the loop can provide a cooling tower or backup heating source will be required to maintain loop temperature.

STEP 7: Assign the Backup Boiler as the Backup Heat Source. A cooling tower is assigned automatically.

 The thermal storage capacity represents the amount of fluid in the entire system, including the borefield, for the ground source heat pump (GSHP) and water source heat pump (WSHP) systems. If the size of the well field has not been determined, users are encouraged to enter a value that approximates the expected size.
    5                       288

   10                      144
   15                        96
   20                        72
   25                        58
   30                        48
WshpTairMin = WDDB, deg F
WshpTairMean = Yearly average OADB, deg F
DryBulbAvemo = Monthly average OADB, deg F
WshpEwtMax = WshpTairMean + 0.8*(WshpTairMax - WshpTairMean)
WshpEwtMin = WshpTairMean - 0.4*(WshpTairMean - WshpTairMin)
*** These equations based on Figure 3.13 from the IGHSPA manual.
WshpACoefClg = WshpEwtMean - WshpBCoefClg * WshpTairMean
WshpBCoefHtg = (WshpEwtMean -WshpEwtMin) / (WshpTairMean - WshpTairMin)
WshpACoefHtg = WshpEwtMin - WshpBCoefHtg *WshpTairMin
WshpEwt = WshpACoefClg+WshpBCoefClg*DryBulbAvemo
WshpEwt = WshpACoefHtg+WshpBCoefHtg*DryBulbAvemo
 When Custom is selected the user must create a custom geothermal schedule within the Schedules Library which Trace uses to specify the monthly loop water temperature.
 When vertical bore is selected the ground loop is configured as a vertical borehole-type ground loop heat exchanger and modeled using an algorithm described by Yavuzturk and Spitler. (See Yavuzturk, C., J.D. Spitler. 1999. "A Short Time Step Response Factor Model for Vertical Ground Loop Heat Exchangers." ASHRAE Transactions. 105(2): 475-485.) The characteristics of the bore field must be previously defined in an Energy-Plus formatted file (IDF) exported from the GLHE-PRO 4.0 program. (GLHE-PRO is distributed by the International Ground Source Heat Pump Association through their web site.)

Note: TRACE requires both a cooling tower and a backup heating source when modeling ground source heat pumps.
In TRACE, the loop temperature is maintained between the Design enetering Condeser temp. and the minimum condenser operating temperature (typically 40°F). Thess temperatures are entered on the Options tab of the ground source heat pump in the Cooling Equipment Library:

If the ground loop temperature exceeds the design condenser entering temperature  (85°F in this example)  the cooling tower, located downstream of the ground loop, is started to reject the excess heat. The tower will operate until the loop temperature is drops below the design entering temperature. To reduce or eliminate the use of the cooling tower raise the condenser design entering temperature.

If the loop temperature drops below the minimum condenser operating temperature, 40°F in this example, the backup heat source is enabled. The backup heat source will operate until the loop temperature rises above minimum condenser operating temperature.
The cooling tower and backup heating source serve as indicators that additional heat rejection or backup heati is required during the simulation. If the Equipment Energy Consumption Report shows energy consumption by either the cooling tower or backup heating plant, users should review the inputs for the condenser temperatures, the capacity of the heat recovery portion of the heat pump, and the capacity of the loop itself. 

STEP 8: Set the Reject condenser heat field to Ground loop.
When the Reject condenser heat field of the Create Plants - Cooling equipment tab filed is set to "Ground loop", TRACE 700 will automatically create an export file during the ENERGY calculation which contains the cooling plant's total monthly cooling and heating loads in addition to the monthly peak loads. These loads are those seen by the ground source heat pump equipment and not the loads seen directly by the ground loop.
The export file is a text file that is saved in the same location as the project (TRC) file, with the same filename as the project, but with a .GT1, .GT2, .GT3, or .GT4 file extension where the number represents the corresponding alternative.

Clg/Htg Consumption (kBtu),TotalMonthlyClgLoads(1-12),TotalClgLoad(13),TotalMonthlyHtLoads (14-25),TotalHtgLoad(26)
Clg/Htg Demand (Btuh), PeakMonthlyClgLoads(1-12),PeakClgLoad(13),PeakMonthlyHtgLoads (14-25),PeakHtgLoad(26)
The export file can be imported into GLHEPRO, GLD, or any other program, used to size ground wells for GSHP systems that allows data to be imported from a geothermal export file.  

STEP 9: Select one of the GLHE options with the appropriate wellfield entering and leaving water temperature difference in the Thermal Storage Type field.
Note: All water source heat pumps must have a Heat Pump Loop Storage tank specified in the Thermal Storage "Type" field.
When a thermal storage type is specified, TRACE 700 generates a thermal storage report for ground-source heat pumps which is available after calculating the file in the Energy Consumption section on the Analysis tab. The Thermal Storage report provides an hourly profile for ambient conditions and plant-level cooling loads, as well as heat pump loads, heat pump energy consumption, and condenser-loop temperatures for hot and cold storage applications.

STEP 10: Enter the capacity of the loop (including the well fields) in the Thermal Storage section of Create Plants:

Here is a way that geothermal heat pump system capacitance can be estimated, assuming the Heat Pump Cooling Design DeltaT (HPCDDT):

For each ton of cooling in an hour, 12,000 Btus of heat will be rejected to the loop:

Q = M x Cp x DeltaT

Using the Cp for water (1 Btu/lb-degF):

12,000 Btu/hr (per ton) = Y gallons (per ton) x 8.34 pounds / gallon x 1 Btu / lb-degF x HPCDDT deg F

Solving for Y yields:

HPCDDT          Gallons/ton

There are two library values in TRACE, but they may not be sufficient in size for the particular application. Users are encouraged to run the simulation again once the capacity has been determined. This process may require several simulations before an adequate value is determined.
round Loop Design Software
TRACE 700 was not designed to size well-fields for Ground Source Heat Pumps but there are several programs that can perform these calculations.
GLHEPRO is developed as an aid in the design of vertical borehole-type ground loop heat exchangers used in geothermal heat pump systems. For more details, visit
Ground Loop Design (GLD), a Windows·-based geothermal HVAC software design package created by Gaia Geothermal is now available for system designers. For more details, visit
Note: These programs are not affiliated with, or supported by, Trane. 

STEP 11: Apply your changes.

STEP 12: Click on the Controls button at the right side of the screen.

STEP 13: Click on the Cooling Plant and Geothermal Controls button at the right side of the screen.

STEP 14: Select one of the TLoop Ent Bldg options in the Plant Controls - Geothermal Loop editor. This field defines the method TRACE 700 uses to compute the monthly ground loop temperatures.
 Ground Loop Temperature Calculations
TRACE is able to compute the ground loop temperature using several methods: IGSHPA , Custom or Vertical Bores.
IGSHPA (International Ground Source Heat Pump Association)
Calculates the average monthly ground loop temperature (GeoEwt, the temperature of the loop fluid entering the building after circulating in the ground) as a function of the selected weather location per the algorithms noted in Figure 3.13 of the IGHSPA manual. These values are generally representative of a shallow ground loop heat exchanger but should be used with extreme caution because the actual GeoEwt is a strong function of the soil conditions, the ground heat exchanger configuration, building loads and many other factors.
When the IGSHPA method is selected TRACE does not explicitly calculate ground-coupled heat transfer for its GSHP model. Instead, TRACE calculates an average monthly ground loop temperature (the temperature of the loop fluid entering the building after circulating in the ground) as follows:
a) At the start of the energy simulation, the following values are calculated:

*** Air temperature range

WshpTairMax = SDDB, deg F

*** Ground loop temperature range

WshpEwtMean = WshpTairMean 

*** These coefficients are used to estimate the initial loop water temperature entering the building after circulating in the ground. 

WshpBCoefClg = (WshpEwtMax- WshpEwtMean) / (WshpTairMax -WshpTairMean) 

b) For each month, this initial ground loop temperature is then given by:

IF (DryBulbAvemo >= WshpTairMean) THEN 

c) WshpEwt is not allowed to fall below the TcondDsnMin defined in the Cooling Equipment library (a mixing valve that mixes warmer return building loop WSHP water with the cooler entering ground-coupled loop water would maintain this value when necessary)

The storage tank size represents the thermal capacity of the loop fluid which affects how much the loop temperature in the building increases or decreases each hour depending on how much heat is added/removed from the loop. This hourly in-building loop temperature is used to determine the hourly performance of the heat pump. This algorithm will then iterate to determine the steady state loop temperature/heat pump performance since the two are dependent on each other.

Vertical Bore
For information on importing custom geothermal fields, click here.

STEP 15: Close all of the controls editors.
STEP 16: Click on the heating equipment tab at the bottom of the Create Plants editor.
STEP 17: Select a boiler.
Note: Trace requires a backup heating source for all water source heat pumps.

STEP 18: Enter the full-load energy consumption for the circulator pump.

STEP 19: Close the create plants editor and assign the heating and cooling coils to their respective plants. 

A common variation of the water-source heat-pump system uses earth as both a heat source and a heat sink. Known as a ground-source (GSHP) system, this variation takes advantage of the relatively constant 45°F to 65°F temperatures that exist 20 to 30 feet below the surface. When buried in the ground, the high-density thermal plastic pipe acts as a heat exchanger. During the cooling season, it transfers the heat absorbed by the heat pumps to the ground for storage. When heating is needed, the heat exchanger recaptures the heat from the ground and returns it to the building.
If properly designed, an applied GSHP system does not require a cooling tower. Aesthetically, this means that all of the heat from the building can be rejected without any visible sign of a cooling system. A boiler is also unnecessary if the heat pumps can satisfy the entire heating load, which saves initial cost and floor space.

  • GSHP systems are more expensive to install, but less expensive to operate, than conventional water-source heat-pump systems. Perform a life-cycle cost analysis to determine the economic viability for a particular application.
  • Installation requires excavation, trenching, or boring by a qualified contractor.
  • Ground-coupled loops can be installed in a horizontal, vertical, or spiral configuration. Available land, soil conditions, and excavation costs will determine the appropriate choice for a given application.

Disclaimer:  Content above sent from Trane Trace Support in 2012

Tutorial from my Penn State Architectural Engineering Thesis Research
Alex Quercetti
Trane Trace Support