LoopLink GSE Update

Our geothermal savings estimation API, LoopLink GSE, recently received an update to improve accuracy and performance. We will start with what got better then talk a little about technical changes that will impact customer implementations.

More Accurate Utility Rates

In version 1 of the GSE API, we took statewide average utility rates and applied them to any search which didn’t include custom rates. In this update, we now search (in the US only) for local electric rates and apply those to the estimate. So, if your customer searches their home address we can typically identify the correct electric utility provider and rate.

We have yet to find a house level rate lookup tool for natural gas, fuel oil or propane. So those energy prices are still a statewide or regional average depending on data availability.

We know it isn’t optimal but due to the difficulty in finding consistent information for all countries, searches outside the US will resolve to the US national average for a given energy type. As demand increases in other countries we will look to improving our defaults. For now, know that if you intend to support other countries your best results will come from asking the homeowner for utility pricing.

Know the Place?

A place object has been added to the response which enables you to identify the location we found for the estimate. At first blush this doesn’t seem that valuable. After all, the user provided the location to initiate the request. The value is that now you have a way to provide feedback to the user to ensure that the place we found was in fact the place they searched.

Technical Note: We moved geocoding attribution data into this object… it just made logical sense to tie the attribution to the result.

Updated Load Model

We are always looking at our load model and working to provide more accurate results with the limited information we require from homeowners. In this update we did more work on tweaking our advanced parameters to account for duct placement, seal and insulation in a more accurate way.

Better Security and Accounting

Version 1 was a little naive in its implementation of Cross Origin Request Sharing (CORS). We have bolstered this method and improved our ability to identify sites that are registered to make requests as well as improved the accuracy of our per site request counts. This will greatly simplify your ability to make requests against our system and allow us to provide you with more accurate usage statistics.

Logging and Retrieval

We noticed that an awful lot of homeowners come back and enter the exact same information into the system multiple times. Rather than rerun these requests we have implemented a logging function that will store requests for up to one month.

We provide a unique estimate ID with each response that can be requested directly. So, now you can get a homeowner’s email and send them a link back to their estimated savings or send a local dealer a copy of the link with the homeowner estimate.

We do not accept or store contact information so it is up to your team to fill in those blanks.

GET or POST

In LoopLink GSE 1.0 we required all requests to be sent as a POST. This is no longer the case. You may now submit your data with a GET or POST. All other request methods are restricted.

Change Your Request Structure

In our first iteration we tried to build GSE to be as permissive as possible. We allowed users to just send us a location field that contained anything from a complete address to just a postal code. The tool worked but the search was buggy and while it always returned a result, the result may have been for the wrong place entirely.

To deal with this issue, we now ask for structured requests so we can more efficiently and precisely search locations. So what was previously sent to us as:

• location=1234 Any Street, My Town, SD 12345 USA

Is now sent as:

• street = 1234 Any Street
• city = My Town
• state = SD
• postal_code = 12345
• country = USA

You don’t necessarily need to send us every piece of information but we we now require that you include the country in a search based strictly on postal code.

Search Coordinates Directly

In the ideal interface, your user will run a location search in the browser through Google Maps or a service like Zillow (which provides some square footage information). Which means there isn’t a good reason for us to geocode the location on our end. You can send us coordinates directly which does speed up many of our results. Just remember that any search containing ‘lat’ and ‘lon’ fields will be reverse geocoded to establish rates and other location information.

In the update, you no longer need to provide the ‘geocoded’ flag. We automatically detect the 'lat' and 'lon' fields and handle the request accordingly.

LoopLink RLC Update: Pond Loop GHEX Design

By, Ryan Carda

Pond loops are closed-loop, surface-water heat exchangers. Regulation permitting, any nearby body of water, such as a lake, stream or pond, can serve as a lower cost heat source/sink for a geothermal heat pump system than conventionally bored or trenched systems. That is of course assuming the pond loop is properly designed and installed.

With our latest update to LoopLink^™ RLC, you now have a simple to use tool to properly design a pond loop.

The RLC Approach

LoopLink^™ RLC uses the calculation methods presented in ASHRAE's Design of Geothermal Systems for Commercial and Institutional Buildings (Kavanaugh and Rafferty, 2014) to perform pond loop design calculations. The calculations account for project location (weather conditions), peak heating and cooling loads, GSHP capacity and efficiency as well as the pond temperature, size and condition (i.e. clean water or muddy).

You have the option of designing pond loops in two configurations:

To make things simple, we assume ASHRAE’s minimum spacing recommmendation of 10 feet for both configurations.

As you work, LoopLink^™ RLC will check that the maximum recommended heating and cooling rates are not exceeded (i.e. the pond is large enough and deep enough to accommodate the load) and will display a warning if necessary. Even with those warnings built in, there are some key things to things to think about when designing a pond loop

Size Matters In Cooling

Rejecting heat to a pond in the summer months even in the warmest of locations is fairly easy due to natural convection and evaporation. The most important thing you need to watch out for is the heat rejection rate.

If the pond (reservoir) is too small, you can change the natural temperature of your pond which is bad for the plants and fish. Plus, you can create excessive amounts of evaporation and run the risk of running your small pond out of water… also bad for the plants and fish.

Size Matters In Heating

Water is pretty amazing. One of the most amazing features of water is its behavior at and near freezing. We won’t get into the physics of water freezing but there are two things you need to know about frozen ponds.

1. Ice floats
2. Liquid water is densest at 39.2°F (4­°C)

So, if a lake is frozen at the surface, the temperature of liquid water at the bottom of the lake and it is 39.2°F (4°C). That is of course until we start extracting heat energy out of that water through a long winter.

Size matters in two ways in heating. First and foremost is the fact that if you have too small of a loopfield, you may locally freeze the water around your loops. This will make your loops more buoyant and may lift them off the bottom of the lake causing a host of problems not least of which is the possibility of catastrophic system damage.

The second size issue is the pond itself. If you don’t have a large enough volume of water you may suppress the temperature of the entire body which will again pose a risk to the plants and fish. It is possible to freeze a pond all the way through if the rate of heat extraction is higher than the rate of heat rejection from the soil below the body of water.

ASHRAE Says Size Matters

In any pond loop application, the body of water being used needs to be large enough so that the GSHP system does not alter the natural temperature of the reservoir by more than 1°F. According to ASHRAE, the maximum recommended load for a reservoir is 20 tons/acre in cooling mode and 10 tons/acre in heating mode.

Before designing a pond loop, a detailed study should be performed to ensure that the size of the pond is sufficient given the load and also to find the temperature of the pond in the summer and winter at the installation depth of the loop.

LoopLink RLC Update: Economics of Replacing an Old GSHP

By, Ryan Carda

LoopLink RLC now allows for an economic analysis to be performed that compares a new GSHP to an old one that is ready for replacement. By doing so, we allow the system designer to illustrate the benefits of upgrading to a new GSHP unit from an economic point of view.

Why The Update?

Units that were installed in the 80's and 90's are most likely near the end of their 25-30 year life expectancy. If you couple that with the fact that newer GSHP units are quieter, more reliable, and more efficient than they were 20-30 years ago, you may find yourself on the receiving end of sales contract to replace a unit.

Project Changes

The new option is included on the Operating Cost Summary and Cost of Ownership pages. To perform an economic analysis that includes the estimated operating cost and long term cost of ownership for an older GSHP, you must first check the box to activate the option from the Operating Cost Summary page.

The performance of the old equipment is described by the operating efficiency you specify just as it is for the other comparison technologies. If you have actual operating efficiency averages for the past year (there are homeowners that check) you should use that information. Otherwise, using the old rated efficiency should get you close.

The Annual Operating Cost by Technology and Annual Carbon Dioxide Emissions by Technology graphs will update accordingly as you make changes to the technologies to comare and their operating efficiencies.

After activating the option, you will also be able to perform a long term economic analysis on the Cost of Ownership page to show simple payback as well as long term operating and ownership costs.

LoopLink RLC Update: Account for Fixed Costs

By, Ryan Carda

The original article has been updated to include information about natural gas meter costs which was added two days after the original post on February 1, 2017.

In our latest update to LoopLink^™ RLC, we added the ability for the system designer to account for the fixed recurring annual cost for natural gas meters or to rent,lease and/or maintain a propane or fuel oil tank. By doing so, we allow for more accurate economic comparisons between those heating systems and a GSHP.

Why The Update?

Tank rental is common among homeowners that prefer to avoid the upfront cost of purchasing a propane or fuel oil storage tank. Additionally, a homeowner may opt to rent rather than own so they do not need to worry about the costs for maintenance, re-qualification or repair. In such cases, the cost to rent a tank needs to be included in the overall operating cost for a propane or fuel oil fired heating system. In the case of natural gas systems, meter fees are frequently a part of the total cost and can add up over time.

Project Changes

The new fields are located on the Price & Inflation Rates page. For existing projects (or projects where fixed costs do not apply), the default value has been set to zero. Note that the field asks for fixed costs in dollars spent per year ($/year).

Operating Cost Summary Changes

To keep our numbers as transparent as possible, the operating cost comparison table will automatically display the new information in a separate “Fixed Cost” column (when applicable). The cost will automatically be wrapped into the graph.

Report Changes

Fixed costs are reported on the Prices & Inflation Rates report page. To make room for the new fields, the reporting of system efficiencies was moved to a separate page. As has always been the case, the inclusion of these pages in the pdf report is optional.

LoopLink RLC Update | Variable Capacity Equipment

By, Doug Carruthers

Our latest round of LoopLink^™ RLC updates is focused on the zone and equipment selection options. You can now select variable speed circulators, model variable capacity equipment more realistically and select to use no supplemental heating.

Variable Speed Circulators

Assigning a variable speed circulator allows the system to ramp up and down the amount of flow that is being pushed across the coil and through the ground loop to maintain the target delta-T. For some dual capacity units there is an additional control option that allows you to specify discreet flow rates for high and low capacity operation. By default, RLC assumes the more common control over delta-T.

Variable Capacity Heat Pumps

We additionally implemented full support of variable capacity heat pumps. The equipment has been in the system for some time however, we treated it as dual capacity equipment. Projects in the system that used the original method of variable capacity equipment treated as dual capacity remain untouched. The heat pumps have just been flagged as outdated.

If you would like to go back into your old projects and update them to use a truly variable capacity model, simply open the zones and re-select your equipment.

No Supplemental

There are cases where designers have no intent of using a strip heater or other form of supplemental heat for the system. If the heat pump is sized to 90% or greater in heating, there arguably shouldn’t be very many bin hours where the GSHP system is unable to maintain set point temperature. RLC now gives you the ability to turn off the supplemental so long as you have sufficient heating capacity assigned to the zone.

As a word of caution, just remember that systems without supplemental may have extended run times where the heat pump is simply unable to satisfy the call for heat. This isn’t necessarily a bad thing, but homeowners tend to like their thermostats satisfied.

GSE Power Up

By, Doug Carruthers

GSE is the newest service in the LoopLink^® family and it is one we are very excited to have available. If you aren't familiar with LoopLink GSE, it is a web service for companies in the residential geothermal market that estimates the how much a homeowner could save if they switched to geothermal.

Since this is the first GSE update article, you should note the majority of updates and news we report about GSE will be written more for web-developers than our typical audience of geothermal system designers. We will do our best to keep the nerd lingo to a minimum and include information that is of universal interest.

With the basics out of the way, lets talk about what we have been up to.

Units of Energy

You can now access the total number of units of fuel consumed in an operating mode (heating, cooling, hot water) both annually and monthly. In other words, you can report the number of kWh the heat pump consumes in a year for heating as compared to the number of ccf of natural gas the conventional furnace would use. This is handy if you want to apply your own methods for estimating energy rates after you receive your response. Of course, you could always pass that information to us and we will return your cost and savings.

Monthly Outputs

In the first iteration GSE was built to simply provide annual savings, cost and carbon emissions estimates. In our latest update we added the ability to access that information for every month of the year. This is really useful for generating graphs and charts that can really help in making your interface look professional and approachable.

Carbon Reduction

We added a 'reduction' object to the 'carbon' objects (annual and monthly). This is just a convenience addition that offers direct access to the change in carbon emissions from the conventional system to GSHP rather than requiring client side processing.

Backwards Compatible

We haven't discussed versioning since GSE is so new to us but we wanted to make a note that minor versions of the software will always be built to be backwards compatible. It is how we define our major vs minor versions. Simply put, in minor versions, we won't break your existing interface by dropping support for or changing the name of a key etc. We only expand on the existing response. Major versions may not be backwards compatible with your interfaces but when we get to that point, we establish a sunset policy for legacy version support.

LoopLink RLC- Pick Your Pipe

By, Doug Carruthers

This week we introduced the ability to choose between HDPE 3608, HDPE 4710 and PEX-A for loop piping in all ground loop configurations in LoopLink RLC.

You will notice on all of your old projects, that your pipe dimensions are held and that HDPE 3608 (standard issue in residential applications) is preselected. You can modify your materials and pipe sizes on old projects and new. All HDPE pipe sizes assume DR 11 while PEX-A is always DR-9.

Switching materials will properly account for the different resistive properties of HDPE vs. PEX-A. You will notice that HDPE 3608 and HDPE 4710 perform the same thermally. That is because there isn’t a resistive difference between the two. The difference between the two is that HDPE 4710 has a higher pressure rating. For DR11 at an assumed 74°F HDPE 4710 is rated at 200psi while HDPE 3608 is rated at 160psi. Note that PEX-A is also rated at 160psi at 74°F.

A Couple Little Things

As always there were some minor corrections and tweaks that we made in this update.

1. We now filter comparison technologies in Cost of Ownership to match those selected in Operating Cost. This issue was brought up by a user who deselected all but one comparison option in Operating Cost and was then (understandably) confused as to why they had to choose a comparison technology on the Cost of Ownership page.
2. Trench width values were not updating correctly on screen for horizontally trenched layouts with only one available option for trench width. The calculations were not impacted by this issue. The problem was strictly visual.
3. When adding a Hot Water system to a project, it was possible to select ‘None’ for the hot water system type. The page still showed all of the input fields for an On-Demand design so, if you weren’t paying attention, you could generate an error on save. The page will no longer allow you to input data if ‘None’ is selected as the system type.
4. Print summary checkbox labels are now toggling correctly if you use the Select/Deselect All option.

R.I.P. Deep Earth Temperature Map

By, Doug Carruthers

The Project Details page of LoopLink^® RLC has just received an upgrade. You can now manually override the minimum and maximum outdoor air temperatures used in your design. Additionally, we created a new ‘Estimate Deep Earth Temp’ button which will apply an approximate Deep Earth Temperature to your project based on the specified Bin Data Location.

Manually Override OATs

This addition is for two types of users.

1. Those that perform their system sizing calculations using non-ASHRAE weather conditions.
2. Those required by local rebate providers to document designs at specific temperatures.

In either case, the use of manual values is pretty straight forward. Click the ‘Manually Override OATs’ button and the values assigned are what LoopLink^® RLC will use in energy and performance modelling. The values are limited by the local weather data. That said, it is important that you understand the impact modifying these values has on your design before you use this feature.

Estimate Deep Earth Temp

As many users have noticed, the update to the interface included the removal of the Deep Earth Temperature map. Our reasons for doing this boil down to:

1. The map was dependent on Flash Player and as this article from Wired explains, the internet is actively pursuing the death of Flash Player.
2. The map had limited utility as compared to the simpler and more effective estimation button that we just added.

The estimate Deep Earth Temperature button is possibly too easy to use… click it and an estimated Deep Earth Temperature is calculated as a function of mean outdoor air temperature. For those performing Open Loop designs, water well temperature has the exact same functionality applied.

You can of course double check the value against the map which (in a non-interactive form) now lives in the help. If you have more accurate data from past experience or in-situ testing, the value can still be entered manually.

Shiny New LoopLink RLC

By, Doug Carruthers

You may have noticed some pretty major changes to LoopLink^® RLC this week like... everything is different. We released our updated interface and now that the dust is settled we wanted to take a little time to explain what we did and why.

The simple answer to the question of why we overhauled the interface is mobility and responsiveness. These have been the buzzwords in web design for the past few years and a trend we waited to follow until a significant number of our users began accessing the software from tablets and handheld devices.

The shift has begun and so we are supporting our user’s natural trend to use the device they have at hand. At the same time, updating the interface allowed us to do some important technical and visual things to simplify LoopLink^® RLC and make it lighter weight with respect to data usage which means faster performance regardless of device.

In the end, we have a faster easier to use LoopLink^® RLC that will better support new features and improvements as we move ahead.

Simplified Navigation

We stripped out the redundant navigation on the top of the page and moved everything to right hand side of the screen. This streamlines work flows and puts everybody on the same page during support calls.

Additionally, we largely (but not entirely) walked away from image based navigational cues and moved to text based buttons. The removal of iconography is intended to reduce ambiguity for new users and help facilitate faster load times by reducing the amount of data your computer needs to download to render the finished page.

There are a couple of major navigational changes that we should mention as they may be a little confusing for everyone the first time through.

• You get back to your project list by clicking the logo in the top left of your screen.
• Click on your initials in the top right corner of your screen to access links to account administration, project list or log out.
• The save button is always going to be at the top of the page. As always, pressing enter will also save your changes if you are focused on an input.

Graphs

We completely changed how we create on-screen graphs. The new graphs are lighter weight, faster and interactive. You can now hover over points, slices and bars and read the value directly from the chart.

There are some minor visual differences between the graphs shown on-screen and those in the reports. The plotted data is the same, they just don’t match 100% (yet) because they are built by two very different methods.

Help

The help files have also been redesigned. In fact, we moved the help files to a completely different platform which will make maintenance and enhancement much easier to handle moving forward. The way you get to the help is the same but the new help will be easier to navigate on its own. Plus, it is now accessible without being logged in to your LoopLink^® RLC account. Simply go to help.looplinkrlc.com.

Additional Changes

• Horizontal trench designers, you should note that we no longer ask for the number of flow paths as an input. We ask for flow paths per trench/pit and number of trenches/pits. It is a subtle but important difference.
• We lowered the fidelity of fixed length mode calculation from ±1 foot to ±5 feet. The result of this is a significant decrease in iterations for the system which means faster responses with a minimal impact on overall accuracy.
• Soil tables are no longer directly accessible through the software. There has been a lot of confusion related to soil properties (especially for horizontal applications) as a result we moved the tables to the help files and are providing just our calculators in the software.
• Cost of Ownership is now available for a variable time period (5-30 years) as opposed to a fixed 30 year analysis.

Geo-Connections: Looking Forward

By, Doug Carruthers

We are extremely happy to announce that LoopLink^® PRO, our new commercial design software is now available to the public. With the release of LoopLink PRO, we are planning on some significant changes and improvements to all of the other areas of our business and we wanted to take a minute to share with you what we have planned as we look forward to the year ahead.

Updating All Websites

In the near term, we will be rolling out an updated design for our company site, LoopLink^® RLC and the GeoConnected blog. Each site will have its own distinctive look but there will be common elements that will make accessing information across all of our sites faster and easier. As part of the redesign, we will improve the mobile friendliness of all of our web properties.

LoopLink RLC Updates

We have never hid the fact that we are a small team. While that size provides us some of our greatest strengths, it also gets in the way of us taking on some of the projects that we really want to get done. With LoopLink^® PRO up and running (like a giant geothermal bull of awesomenessitude), we will be turning our focus back to our flagship residential/light commercial program and working through some pretty major changes. Including:

New Look and Feel

We will clean up the existing design and make the site more responsive for mobile users. Many of the design cues will be pulled from the LoopLink^® PRO interface so if you are curious where we are headed, you should check out the PRO interface.

Server Side Power Up

We will be making some critical changes to the parts you don’t see that will help us to improve the parts you do much more efficiently moving forward.

Payment System Upgrade

We will be making significant changes to our check out process that will force changes in account management and will affect current users’ automatic renewal schedule. We will contact all users prior to taking this step with details about what to expect and how you will be impacted.

Headloss & The Upgrades

There are a lot of users who have requested the inclusion of a head loss calculator into LoopLink^® RLC. It will be added this year. In addition we have a few other upgrades and tweaks on our to-do list to tackle. We will determine the short list soon and fill you in on the details.

Training Opportunities

Our roots have always been in education. Over the past year, we have worked hard to expand and improve upon our online courses for geothermal professionals. With the help of our friends at HeatSpring we are proud to offer the following courses.

Entry Level Geothermal Professional

Provides a basic overview of GSHP design, installation, etc. for those looking to learn without the need for certification.

Geothermal Designer Boot Camp + LoopLink Certification

For the residential or light-commercial system designer looking to learn advanced design principles. This course provides hands-on design experience through homework problems that are completed using LoopLink. Get a free LoopLink RLC license when you register.

IGSHPA Geothermal Installer Accreditation

For anyone looking to open themselves to new markets through a working knowledge of GSHP technology . This is a preparation course for the IGSHPA Accredited Installer exam and covers all aspects of GSHP systems - economics, design, installation and commissioning.

IGSHPA Vertical Loop Installer Accreditation

For drilling professionals interested in mastering GSHP installations. This is a preparation course for the IGSHPA Accredited Vertical Loop Installer exam and covers all aspects of GSHP systems - economics, design, installation and commissioning.

IGSHPA Certified GeoExchange Designer (CGD)

For the commercial system designer looking to obtain the highest certification available in the world of GSHPs. This is a preparation course for the IGSHPA CGD exam and provides hands-on design experience through homework problems that are completed using LoopLink PRO. Get a free LoopLink PRO license when you register.

Thank you for your patience while we make these changes.

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You can learn more about LoopLink PRO features or sign up for a free one week trial of LoopLink PRO at looplinkpro.com

LoopLink Update

By, Doug Carruthers

Just when you thought LoopLink couldn't get any better... it does.

Formation Properties Estimators

Regardless of the type of ground heat exchanger design you are working on, you have to provide some information about the thermal properties of the ground. For many users, selecting a representative formation thermal conductivity and/or formation thermal diffusivity has been a stumbling block. The tables can be a little intimidating (especially for horizontal trench) and soil/rock is just something many people don’t know that much about.

In our latest update, we added tools to help estimate the thermal properties of the ground customized to the needs of the type of ground heat exchanger you are designing.

Vertically & Horizontally Bored

In vertically or horizontally bored GHEX, the formation thermal properties are a weighted average of each layer of soil/rock through which the bore passes. You can now create a drill log for either of these types of systems and LoopLink will automatically calculate and report the estimated thermal properties of the formation.

The drill log you define can also be saved and included as part of your printed reports.

Horizontally Trenched

There is a lot going on in the soil table for horizontally trenched ghex and it is intimidating especially for the uninitiated. So, we took some time and thought about how the table is read by a person and created an interactive tool to guide you through the selection process.

Now you just need to specify, the density and moisture range for your formation as well as the basic composition of the soil by percentage of sand, silt, and clay. LoopLink will narrow down your options and make suggestions for the closest 1-3 soils from the table.

Once you make your selection, click ‘Apply Estimated Soil Properties’ and the thermal conductivity and diffusivity will be updated for your design.

It is important to note that these new tools are just providing estimates. Even with a drill log defined, you can still directly set your thermal properties. Which you should do if you have actual formation thermal conductivity test results.

Video Help

Help files are awesome but sometimes we don’t feel like reading either so, we started making help videos. We don’t have them for every section just yet but you will notice a new play button popping up next to the help link in the sections where videos are available.

These are made more for first timers than our old pros but if you get stuck, they can give you a nudge in the right direction. Like everything else in a well maintained system, these are a work in progress and we will continue to add new content and improve over time.

Log In From Any LoopLink Domain

This new feature is something that users of our manufacturer versions will appreciate most. Have you ever Googled ‘LoopLink’, gone to looplinkrlc.com and been told that your log in information is invalid but you KNOW it is right?

Often times, your log in information is correct but, you are on the wrong website. This happens a lot more often than we thought it would when we started building the manufacturer versions so we changed our approach to logging in a little bit.

Now, if you are using good information on the wrong site, we will provide you with a link to the correct site. For a bunch of reasons that are too boring to detail, we don’t log you in automatically but, we now direct you to where you need to be to log in to your account.

Bug Fixes

We do a lot of testing and try to be careful before any release but sometimes it takes pushing our work into the wild to find problems. There were a couple of noteworthy bug fixes that we completed in this release.

• You may now include special characters like é,ô,à,ü,° in the text fields of LoopLink without crashing the report system. We unfortunately can’t support all character encodings. LoopLink will do its best to include these characters in your reports but if the character cannot be reproduced, it will be skipped and your report will still be generated.
• Our explorations into character encodings made it possible for us to switch units of ft^2 in reports to the much cleaner looking ft²… not really an error but it was something that bugged our report designer.
• The ‘% Energy From Geo’ calculation has been corrected for systems that use non-electric supplemental or dual fuel technologies. This issue had no impact on design calculations so critical values like bore lengths, operating costs etc. were unaffected by the error and the subsequent correction.

Is It REALLY Undersized?

By, Doug Carruthers

In our article Warning: Graphic Geothermal Content we explained how to read and use the then new ‘Zone Load and Operating Profile Graph’ for design and sales. At the end of the article we made note of the fact that understanding the distribution of energy as a percentage of bin hours within an operating mode was the tricky part for many new designers and homeowners.

During equipment selection designers tend to fix on the % Sizing. % Sizing is important but it doesn’t tell the whole story. It simply expresses the equipment’s rated capacity as a percentage of the worst case peak heating load. It is a snapshot that doesn’t consider that there are very few hours in a year where the equipment will need to satisfy peak load requirements. Which begs the question, how do you really tell if equipment is undersized?

In his latest stroke of insight Ryan said: ‘Calculate the percentage of the total energy that is provided by the geothermal and display that directly below the heat pump’s percent sizing value.’

Seems obvious now... so we added the output "% Energy From Geothermal" to the zone pages and reports directly below '% Sizing'.

How Does This Help?

Well, now when you are selecting a heat pump that is ‘undersized’ for a space you can see that even though your equipment is sized to 75-80% based on capacity, the geothermal system may in fact supply 95-99% of the total heating energy required by the system. This makes it even easier for you to optimize your heat pump selections during the design. Plus, it gives you a quick way to explain to your customers why it is ok that the equipment you selected is ‘undersized’.

Think of it as a shortcut to explaining the bin hours on the ‘Zone Load and Operating Profile Graph’, which, in our humble opinion, is still one of the most useful graphical tools for understanding and explaining geothermal system operation.

Don’t Forget Operating/Installation Costs

It should be noted that just because the selected equipment is well matched to the space requirements, it doesn’t necessarily mean that it will be the cheapest to operate or install. Play around with combinations of multiple smaller units versus a single larger unit. What you find might surprise you.

Shorter But Dominant?

By, Doug Carruthers

For every geothermal ground loop design, there is a load dominant mode and a length dominant mode. The load dominant mode is the one that will transfer the largest amount of energy to/from the loopfield while the length dominant mode is the one which requires the largest amount of pipe in the ground to transfer that energy based on designer specified entering water temperatures. Most of the time, they are the same, but not always.

When the temperature of the fluid entering the heat pump and the deep earth temperature (DET) get closer together, the amount of pipe needed to transfer heat increases. So, in some system designs, it is possible that the load dominant mode will require shorter loop lengths.

In our latest update we have made it clearer when there is a difference between load dominance and length dominance in a design. On screen, we independently flag the load dominant and length dominant modes when they are different. And, in the reports, your dominance flags have been reworded for clarity.

For those that are really paying attention, fixed length mode works the same as it ever did and only considers load dominance. The reason for this is that Fixed Length Mode is a reverse calculation of EWTs and without adding an obscene amount of overhead (not to mention a false sense of accuracy), it isn’t always possible to obtain exactly equal heating and cooling lengths. So, even when the load dominant mode’s length is shorter, it is assumed that either fixed length mode did not converge on a real solution (which LoopLink flags as an error) or the difference between the two lengths is insignificant with respect to installed performance.

C-C Spacing Down to 10ft

By, Doug Carruthers

By popular request from our users, we reduced the minimum center to center bore spacing (S_B) for vertically bored ghex down to 10ft from 15ft.

We originally set the minimum at 15ft because when bores get much closer than that, they can begin fighting each other and degrade the long term performance of the loopfield. This is especially true in areas with wide temperature swings and greatly unbalanced heating/cooling loads. However, as our users keenly pointed out, in mild climates, 10ft on center is not an uncommon configuration for a loopfield.

We maintained a default value of 15ft because, for the majority of designs, we don't recommend bores spaced any tighter but, for those that need the flexibility, you may now adjust down to 10ft centers.

As always, let us know if there is anything else you would like us to address.

Our Work Is Never Over

By, Doug Carruthers

LoopLink took a page out of the Daft Punk playbook this week and got Harder/Better/Faster/Stronger. After our Major Update of 2013 we found a few performance issues that turned out to be more than just hardware limitations. Generally, most users were not significantly impacted but the slow response could compound very quickly for multi-zone fixed, length projects and in some cases could lock a project out for real time updating.

Fixed length mode intensified the issue because of the nature of what needs to be done in order to calculate a fixed length. For those following along at home in their IGSHPA RLC Manual, you know that the calculation of loop length is dependent on several variables many of which are co-dependent. As a result, there is no mathematical straight line from a targeted loop length to a resultant entering water temperature.

So, LoopLink guesses entering water temperatures (EWTs)… checks if it was right and then systematically improves the answer until a close answer (typically plus or minus 5ft) is found. For each guess, LoopLink has to evaluate every heat pump in every zone and then check the lengths. Add multiple zones and multiple users and boy, that escalates quickly.

In order to improve the efficiency of this process, we had to look for ways to eliminate processes and streamline calculations. In our hunt, we made substantial changes to our core bin-analysis logic and completely revamped fixed length mode. The final result is a 30% average reduction in page response times and an improvement in the overall accuracy of fixed length calculations.

Larger projects using fixed length mode will still take some time to converge on an answer but everything is faster than it once was. Hour after hour, our work is never over and LoopLink will continue to improve.

Check out some ideas on how to use fixed length mode a little more effectively.

LoopLink Update 2013

By, Doug Carruthers

Another year… another major LoopLink update.

This year’s major update includes the usual bug squishes and nip/tuck tweaks to layout and interface but the really big stuff this year is all about adding more flexibility and control for geothermal loopfield designers. We are proud to introduce Heating Offset and Heating/Cooling Start Temperature adjustment as well as a peppering of enhancements that will make your life easier.

Heating Offset

Heating Offset is a new parameter that can be defined on a zone by zone basis. With the Heating Offset, you can now account for static internal gains on the heating side. This more accurately calculates loads and subsequent loop lengths for zones that will have a predictable constant amount of heat generated within the space by equipment and people. The Heating Offset is also used to calculate a Heating Start temperature that better reflects when the space will require the geothermal system to start heating.

Heating Offset Estimator

We could have just put a field on the page and let you figure out your own heating offsets but that isn’t our style. We built a custom Heating Offset Estimator that you can use to estimate each zone’s static internal gains. Input square footage, occupancy, light level, common appliances and/or workstation density and LoopLink will return an estimated heating offset.

Check out the full overview for complete details.

Heating/Cooling Start Temperatures

In early spring and autumn, outdoor air temperatures are comfortable. Windows are opened and we air things out, which means, we aren’t heating or cooling our inside spaces with geothermal. In the past we allowed only a small amount of control over when a system would be in operation. With the heating and cooling start temperatures you are now able to define the temperature at which the building owner is likely to shut the windows and condition the air. This gives you much more flexibility in controlling the hours used in your bin analysis which can have a significant impact on run times and loop lengths.

Check out the full overview for complete details.

Project Summary Improvements

The project summary page was admittedly, a little lack luster. It was a just a list of page names with checkboxes and a button labeled “Generate Report”. We took a little time in this update and thought about how we could improve things (unfortunately, the Nintendo Super Mario Kart emulator was nixed early on).

We ended up changing the layout and organizing the page into sections. We also made it easier to specify which sections you want in your report with section based toggles. Additionally, we improved the error detection logic and made it easier to add elements to your LoopLink projects directly from the summary page.

Print from Project List

Have you ever just needed to run your project summary without changing your project? Now you can! We added a print button on the project list that will allow you to jump directly to the new and improved project summary page from your project list.

Everything Else

We definitely have not and will not list ALL of the changes we have made... most of them are just too small for anyone but us to care about. Below are some of the smaller but still noteworthy changes we made this update.

• Hot water costs and CO₂ Emissions are now accounted for in the Operating Cost Summary.
• We improved the section labeling to add clarity to what information you need to provide within each section.
• It is now possible to remove screen and print logos from your account.
• Error Messages now detect when you edit a problem field and clean themselves up as you work.
• Save Confirmation messages are now set to fade out once you make a change on a saved page.
• Dual Fuel Runtime and Supplemental Runtime have had their labels updated to Dual Fuel Bin Hours and Supplemental Bin Hours to better reflect what they are reporting.
• Improved print resolution of Zone Load and Operating Profile Graph.
• Users can now change the name on their account.
• Gain Level on project details changed to Building Type to improve clarity.

Heating Offset

By, Doug Carruthers

The prevailing wisdom in peak load calculation is to ignore internal gains (heat energy generated by occupants and equipment) on the heating side. This approach guarantees that the heating system will be able to keep the space at set point temperature in the event that these heat sources are turned off or removed from the space. This is the most conservative design practice and should be followed in all cases if there is a reasonable possibility that the usage profile of the building will change.

That said, there are many LoopLinkers that have requested a means of accounting for static internal gains (energy that will always be there) to minimize the size of the installed loopfield and equipment costs based on a designed usage profile. This posed a difficult problem for our engineers and sparked surprisingly lively debates about whether accommodating these loads was ‘valid’ and in the best interest of the industry.

Ultimately, we decided to add the new Heating Offset field to each zone. The Heating Offset allows the system designer to account for static internal gains in each zone. The energy in the heating offset is pulled out of every heating bin during the bin analysis so it can have a significant impact on the final loopfield design. Additionally, the heating offset will change the calculated outdoor air temperature at which the geothermal system will start supplying heat (Heating Start Temperature). Which is why, we at Geo-Connections all agree that Heating Offset should be used with caution.

Consider Yourself Warned

The Heating Offset has the potential to significantly reduce loop lengths on the heating side. If an arbitrarily high heating offset is defined, the loopfield will not be sufficient to meet demand. In other words, your customer will not be happy. Also important to note is that if the next building owner changes how they use the space, your carefully calculated usage profile is irrelevant and your undersized loopfield could leave them with a low opinion of geothermal.

When is Heating Offset Appropriate?

Heating Offset should only be used in zones with known long term usage profiles. Accounting for a refrigerator in the kitchen is a reasonable application since there is a low probability that the next homeowner will not have a fridge. Accounting for six televisions in the living room is probably not a great idea since the next homeowner isn’t likely to have a similarly awesome vegetative command center.

Heating Offset can also be used with systems that include passive heating strategies that have a known minimum amount of energy that they will store in the building. The key here is that the heating offset should not exceed the worst theoretically possible performance of the passive system in the design year. This will minimize the likelihood of under-sizing the loopfield and becoming overly dependent on supplemental or dual fuel systems on your coldest days. This also helps in the case of a future building owner not understanding the passive heating strategy and planting trees in front of those south facing windows.

Heating/Cooling Start Temperatures

By, Doug Carruthers

Heating/Cooling Start Temperatures define the outdoor air temperatures at which a building owner will begin operating their heating or cooling system. In ASHRAE manuals and HVAC books these are referred to as Balance Point Temperatures because they are typically calculated as the temperatures at which the energy lost is perfectly balanced with the energy gained either to or from the space.

In the latest LoopLink release, we added the ability for users to control their Heating/Cooling Start Temperatures in an effort to offer more granular control to the geothermal system designer when specifying the operating conditions of each zone. Heating start temperatures are calculated as a function of your peak heating load, your building type and your specified heating offset for the zone. Cooling start temperatures are just a simple input that accepts values from the default cooling start (defined by selected Building Type) up to 80°F.

Control Your Dead Band

The difference between the heating and cooling start temperatures is known as the ‘dead band’. This ominous sounding term just reflects the fact that the geothermal system is not running and is represented on the Zone Load and Operating Profile graph as the thin white area. This unassuming bit of space contains bins and each bin represents the amount of time per year, in your design location, the outdoor air temperature will fall within a specific 5°F temperature range.

LoopLink looks at each bin and calculates the amount of energy that will be needed to maintain the specified set point temperature. So, the more bins that fall within your dead band the fewer number of bin hours LoopLink will analyze and add to your equipment run time.

This level of control allows you to more closely match your design to how your customer will actually use the space. For example, in most homes the air conditioner isn’t going to be turned on until outdoor air temperatures are well above 65°F or 70°F, especially if it isn’t humid out. People will open their open windows and cool their homes for free.

In the past LoopLink simply used your specified Gain Level (now Building Type) to assign a heating and cooling start temperature to all zones in your project. This makes for systems that are conservatively designed but can result in slightly skewed equipment runtimes which can adversely affect operating cost estimates and long term savings estimations. With the new heating and cooling start temperatures you can match your designs to your customer’s behaviors giving you, and them, more realistic estimations of performance and long term costs.

Gain Level is Now Building Type

In the past, LoopLink asked you to define a Gain Level on the project details page which roughly described the amount of heat energy emitted from people and devices in the space; commonly known as internal gains. The Gain Level was used inside LoopLink to approximate heating and cooling start temperatures. Low gain level structures were modeled such that cooling started when the outdoor air temperature (OAT) was 70°F and heating started when the OAT got down to 62°F. Medium gain level buildings used 65°F and 57°F while high gain structures used 62°F and 52°F.

The Gain Level parameter still exists but, in our latest LoopLink update, we have reimagined how it is used. Now, instead of low, medium or high internal gains, you select a Building Type from Storage/Warehouse (low), Residential (medium) or Light Commercial (high). The building type sets the default heating and cooling start temperatures for the project just like the Gain Level parameter did but now when you create a zone you can modify these temperatures to better control your energy and operating cost analyses.

Why Did We Change It?

The Gain Level parameter was the most unLoopLinky field we had. It required more on screen explanation than any other field and the explanation, never really conveyed what we intended. As a result it appears that the majority of system designers simply skipped over the field and just left it at default (96% of all projects are set to medium gain).

This isn’t a bad thing. The mid-range heating and cooling start temperatures won’t cause a system to be modeled incorrectly they just might skew the operating cost estimates and long term savings a bit. So, to make the parameter more approachable, and system cost estimates more realistic, we switched Gain Level to Building Type and put the corresponding default heating and cooling start temperatures for each type on screen.

It is now easier to see and understand what you are defining. We hope this will add clarity to your design process and help you provide even more accurate economic evaluations to your customers.

New Horizontal Configuration Added

Late last week, we added the 6-Pipe Rectangular configuration to the standard horizontally trenched GHEX design options. The new configuration model is also called a 2-layer 3-pipe and is one we were asked to model by several users.

We won't bore you with all the details but there is a lot more than just drawing pictures and changing the drop-down when we add a new GHEX option to LoopLink. The new layout has been modeled for 2ft, 2.5ft and 3ft trench widths. Let us know if there any other GHEX configurations you would like added to LoopLink. We add according to popular demand.