Getting Started with the SLASH-D

 

This guide is an introductory document for using the SolarLogic Assisted Solar Heating Design website only.  It is not intended to be comprehensive.  Users who want training on the SLASH-D and the SolarLogic SLIC should sign up for one of our trainings using the form available on the SolarLogic website: www.solarlogicllc.com. The SLASH-D website works with IE version 8 or later, Chrome and Safari.

 

Overview:

1.     Yellow boxes on the tabs require an input. You must have yellow box entries for the calculations to be proper.

2.     White boxes are optional inputs which can improve the calculated results for your job.

3.     Grey boxes are calculated output values.

 

Up Top:

1.     Enter a Job Name and a Tag.  Use only alphanumeric characters – no special characters.  You can then Save the job whenever you like as you are working on it.  The intent of the Tag is to have different versions of the same job to compare as you look at options. For example, tags might be things like “extra solar panels” or “no heat in the garage” or “with spa”, etc.

 

Job tab:

1.     State and City. Select the state and city for your job (default: New Mexico, Albuquerque).  This sets up the latitude and the 30-year weather data (NREL data base) used for calculations.  If there is no city available in your area, use another city that you think is a good approximation to the correct latitude and average coldest winter day.

2.     Building Performance. Select the approximate UA of the building by choosing from the building performance pull-down (default: average).  The UA that the SLASH-D uses is displayed in Heat Loss Rate box.  If you have a calculated value for the building, select “Use Calculated Heat Loss Rate” and enter that number in the white box labeled the same.

3.     Comfort Target.  Enter the temperature at which you think the homeowner will want to keep the house, i.e., where the homeowner will set the thermostats (default: 68).

Special Case Example: To use the Comfort Target to compensate for not having a city nearby with the correct average winter temperature.  Santa Fe is typically 5-10 degrees colder than Albuquerque, but not far off in latitude or solar resource (insolation).  To set up the SLASH-D for Santa Fe calculations, we choose Albuquerque as the city and set the Comfort Target 7 degrees higher than we think the homeowner will actually use, e.g., the default we would use is 75 instead of 68.  This makes the building require a more correct number of heating degree days for the calculations.

DHW tab:

1.     DHW Usage. Input the daily gallons of DHW use you expect (default: 50).

2.     DHW Setpoint. Select the “shower temperature” you want for the DHW tank, i.e., the water temperature below which the boiler or other backup heat source should come on to make DHW (default: 120).

3.     DHW Tank Capacity.  If the job is a retrofit and you are keeping the DHW tank, input the correct value (default: 50).  If the job is new construction, or if you intend on replacing the DHW tank as part of the job, a good place to start is about 2 times the DHW usage.  For example, for a house with three people, enter 60 gallons for the DHW usage (20 per person) and 120 for the DHW tank capacity.

4.     DHW Tank Heat Loss.  If you know something about the tank, you can input what you believe is the accurate number for heat loss from the tank. Otherwise, leave the default of 1 degree/hr.

5.     Leave everything else at default values.


Solar Components tab:

1.     Solar Contribution. Choose the desired amount of solar contribution to the annual combined space and DHW heating loads, from low to high (default: medium).  Medium means that approximately 50% of the heating loads will be provided by solar.  The range covers from about 30% to about 70%.

2.     Collector Size. Select the collector size you would like to use, thinking about mounting, roof space, etc. Larger collectors can be more cost effective because of the cost of mounting hardware and labor, but 4x8 is usually the least expensive in $/SF for the collector itself (default: 4x8).

3.     Platform Pitch.  This is the angle of the surface on which you will mount the collectors.  A flat roof is 0; a south facing vertical wall is 90. The default is 0 (Our headquarters are in New Mexico).  The calculated horizontal separation is the required distance between collector banks to avoid shading, from front to front, as measured along the platform, if the collectors are mounted in landscape orientation. For portrait orientation, use the vertical separation number.

4.     Max Panels.  This is the maximum number of panels allowed in the first bank of collectors.  This maximum can be used to force the plumbing diagram to use two banks of collectors if you want.

 

Manifold tab:

Note: On the Manifold tab, you only need to enter one zone on one manifold to start off the calculations.  You can thus do a really quick rundown of the job by specifying the entire house as one zone, using the total heated square feet.

 

1.     Manifold Type, Circulators and Tube Spacing. Choose the appropriate menu items for your job for each manifold separately.  “Circulators” is to choose between using zone valves or zone circulators.

2.     Zones. Enter each zone and its square foot area.  For radiant floors, enter the number of tubing loops in the zone if you know it.  For baseboard zones, enter the number of baseboard linear feet and/or the number of baseboard plumbing loops if you know them.  The loop numbers and/or lengths are used to calculate expected required flow for the zones.  If you require a specific flow rate for a zone other than what the program calculates, you can make the flow be a different value by changing the number of loops to get the value you want.  To delete a zone, blank out its name and then enter 0 for the square feet.  The zone will disappear.  You can swap zone numbers via the zone number pull-downs on the left (even between manifolds).

 

Manifold G tab – this tab takes a bit more explaining and is for outdoor pools, spas and ice melt zones. You can learn how to use this tab in our trainings, particularly the Expert Training.  Very briefly:

3.     Ice Melt Zones. Use a nominal 1 gallon/min for every 600 SF of ice melt for the flow required.

4.     Spa. Choose the spa characteristics and a flow of 5 gallons/min for a starting point.

5.     Pool. You can put in the pool volume and a nominal flow of 8 gallons/min, but the most important numbers for a pool are the daily average heats needs in KBTU.  These can vary enormously depending on the pool size, shape, seasonal use and whether it is covered or not.  The average daily heat use organized by month needs to be approximately correct in order for the SLASH-D to calculate solar panel sizing and tilt. These numbers can be gotten from your pool designer or other specialist.

 

 

Congratulations, you’re done!

 

Useful Outputs (most outputs are self-explanatory):

1.     Job tab:

a.     Load Total – the total annual heating requirements (MegaBTU, MBTU) for space plus DHW (this includes pool, spa and ice melts if these loads exist).

b.     Heated Sq Feet – check that you’ve got the right number of total square feet.

c.      Leftmost graph – BTU Load versus Resource.  This graph displays the total heat load in BTU/day by month (green), the solar resource (various colors) for collector mounting angles from 0 to 90 degrees, and the solar resource (black) for the selected collector mounting angle (either the SLIC-recommended angle or the user selected angle if the recommended one is overridden.

d.     Center graph – BTU Saved versus Panel Tilt.  This graph displays the total annual BTUs saved (red) with solar (MBTU/yr) for collector mounting angles from 0 to 90 degrees, and the total annual BTUs saved (green) for the selected collector mounting angle (either the SLIC-recommended angle or the user selected angle.

e.      Rightmost graph – Dissipation versus Panel Tilt.  This graph displays the excess heat needed to be dissipated on the worst day  of the year (largest difference between load and resource) in KBTU/day (blue) for collector mounting angles from 0 to 90 degrees, and the needed dissipation (green) for the selected collector mounting angle (either the SLIC-recommended angle or the user selected angle.

2.     Flow Center tab:

a.     Plumbing diagram in block form – each block is detailed in another tab by the same name.

b.     Parts list – only for the items shown in detail on this tab.

3.     DHW tab:

a.     Recommended Heat Storage – the total number of gallons required for heat dissipation, if necessary, and/or heat storage for non-mass zones, if necessary. The actual gallons of storage used will override this if you want.  Use the “Storage Tank Override” pull-down.

b.     Plumbing diagram – for this part of the system (one of the blocks on the Flow Center tab diagram).

c.      Parts list – only for the items shown in detail on this tab.

4.     Aux Source tab:

a.     Plumbing diagram – for this part of the system (one of the blocks on the Flow Center tab diagram).

b.     Parts list – only for the items shown in detail on this tab.

5.     Solar Components tab:

a.     Recommended Number of Panels – this will obviously change depending on several different choices you have made, including collector size. The actual number of collectors used will override this if you want.  Use the “num panels” pull-down.

b.     Recommended Angle – for mounting the collectors.  This is the angle relative to horizontal, not relative to the platform.  The actual mounting angle used will override this if you want. Use the “angle” pull-down.

c.      MBTU Saved per Year. An estimate of the number of MBTUs the solar heating will save on an annual basis.  This is NOT the number of BTUS the panels will produce.  It is the number of MBTUs that will actually get used by the system, i.e., delivered to useful loads throughout the course of the year.  A degrading factor for transmission and heat exchanger loss is included in the calculations.

d.     Plumbing diagram – for this part of the system (one of the blocks on the Flow Center tab diagram).

e.      Parts list – only for the items shown in detail on this tab. 

6.     Manifold tab:

a.     Plumbing diagram – for this part of the system (one of the blocks on the Flow Center tab diagram).

b.     Parts list – only for the items shown in detail on this tab.

7.     Manifold G tab:

a.     Plumbing diagram – for this part of the system (one of the blocks on the Flow Center tab diagram).

b.     Parts list – only for the items shown in detail on this tab.

 

8.     Parts List tab – the accumulated list of parts from all the other tabs. The parts list does not include ancillary items specific to the job, such as copper tubing, PEX tubing, small fittings, adapters, mounting hardware for piping and the collectors and glycol.  It also does not include the boiler.  (We’re working on the pricing section.  Soon, you will be able to put in and store your own pricing and have the SLASH-D come up with a real total dollar estimate of parts for you.  This feature should be operational in the fall of 2012.)

9.     Admin tab – you can change your password here at any time.