LoopLink RLC Help

Zone

The zone page is used to create or modify a zone within a project. Up to 10 zones are allowed.

Zone Details

Enter information about peak heating and cooling loads & interior thermostat set points.

Zone # / Name: Enter the number/name/description for the zone.

Peak Heating Load: The maximum rate at which heat must be added to a space to maintain the thermostat set point, commonly calculated in accordance with ACCA Manual J for residential applications. The peak heating load occurs when the outdoor air design temperature is reached.

Heating Set Point: The thermostat setting for the space during the heating season, commonly assumed to be 70 degrees F.

Peak Cooling Load: The maximum rate at which heat and moisture must be removed from a space to maintain the thermostat set point, commonly calculated in accordance with ACCA Manual J for residential applications. The peak cooling load occurs when the outdoor air design temperature and humidity level are reached.

Cooling Set Point: The thermostat setting in the space during the cooling season, commonly assumed to be 75 degrees F.

Space SHF (Sensible Heat Factor): The portion of the total cooling load that can be attributed to sensible cooling load, defined to be the sensible cooling load divided by the total cooling load and expressed as a decimal.

For more information about heating and cooling load calculation procedures, refer to Section 3.2 (Chapter 3, starting on page 2) in IGSHPA's Ground Source Heat Pump Residential and Light Commercial Design and Installation Guide.

Load Estimator

The Load Estimator will estimate peak heating and cooling loads for the project based on geographical location along with the information provided. The loads generated by the Load Estimator can be used to estimate required equipment capacity and GHEX design lengths along with annual operating costs, carbon emissions, and cost of ownership over a 30-year time period.

Create Estimated Load: Click on the New Load Estimate button, enter information about the size and construction of the home and click Save to use the entered information and export the estimated loads to the ZONE page.

Edit Estimated Load: Click on the Edit Load Estimate button to adjust the loads for the zone.

Delete Estimated Load: Click on the Delete Load Estimate button to remove the estimated loads and to enter actual design loads. Once the Load Estimator is removed, you will be able to add additional zones.

Estimated Loads are for BUDGETARY USE ONLY and are approximations not to be used for the design of a project. The Load Estimator is only available for single-zone projects. If the Load Estimator is activated, the ADD NEW ZONE feature will be locked. If the project already has more than one zone, the NEW LOAD ESTIMATE feature will be locked.***

Heating Offset

Define a heating offset (Btu/hr) to account for consistent internal gains within the zone.

Research has shown that traditional energy models can overpredict annual heating costs. This is due to the fact that a portion of the heating energy requirements for a residence can be offset by "free heat generation" from internal gains such as regular building occupancy or lights and appliances that are used on a regular basis.

IMPORTANT: Use caution when defining heating offset values as they can significantly impact required loopfield lengths/depths. The heating offset that you define for the zone should account for CONSISTENT internal gains in the space, which may or may not be the internal gains that occur during peak cooling conditions.

Season Start Temperatures

Season start temperatures are the outdoor air temperatures (OATs) at which your zone will require heating or cooling.

Heating Start: The OAT where heating will be required in the zone. The heating load is assumed to be zero when the OAT is greater than this value. Heating start temperature is calculated based on the Peak Heating Load, Heating Offset, and Heating Set Point.

Cooling Start: The OAT where the cooling system will be turned on in the zone. Note that although the cooling load may be greater than zero at lower OATs, the cooling system will not operate until the OAT is above this value. For example, cooling may be required in a home when the OAT is 65F but the homeowner may choose to open the windows for "free cooling" until the OAT is above 75F.

The Cooling start temperature should be defined according to the preferences of the building owner.

GSHP Selection

Specify the equipment selected to serve the zone.

Heat Pump Type: The type of GSHP unit that will serve the zone. A Water-Air GSHP unit provides heating and cooling by distributing conditioned air to the space through ductwork. A Water-Water GSHP unit provides heating and cooling by distributing heated and chilled water to the space either through a hydronic distribution system or via radiant heating/cooling methods.

Capacity: Can either be "Single" for single capacity GSHP equipment or "Dual" for two-capacity GSHP equipment.

# Heat Pumps: The number of same-sized GSHP units to serve the given zone

Manufacturer: Select the GSHP equipment manufacturer of choice.

Model: The list of models available for the selected GSHP equipment type, manufacturer, and capacity.

For more information on selection guidelines, refer to Section 3.4 (Chapter 3, starting on page 10) in IGSHPA's Ground Source Heat Pump Residential and Light Commercial Design and Installation Guide.

Circulating Pump Details

You may choose to use a variable speed circulator or maintain the default of a constant flow. Note that for a variable capacity heat pump, you will necessarily have a variable speed circulating pump.

Variable Speed Circulator: Check this box to model your system using a variable speed circulator. By default, all circulators are model as though they are controlled by the temperature change across the heat pump. Systems using dual-capacity heat pumps will have the option of controlling based on gpm.

Control Circulator Based On GPM: Check this box to model your circulating pump such that it discretely changes flow when switching from high capacity to low capacity. This option is only available for dual capacity heat pumps.

Back-Up System Details

Method

None: The option to apply no supplemental heat is available only in situations where the heat pump(s) assigned to the zone are at least 90% sized. The zone will be forced to use a back-up system (supplemental by default) if insufficient capacity is assigned.

Supplemental: Choose this method if the auxiliary heat source is able to operate at the same time as the GSHP system. For water-air systems, the only supplemental heating method allowed is electric resistance. For water-water systems, supplemental heating can be provided with any type of boiler.

Supplemental w/ Dual Fuel (Water-Air Systems Only): Choose this method if a combination of supplemental heating with electric resistance and dual fuel heating with a furnace will be used. Remember, when the dual fuel system (furnace) activates, the GSHP must be turned off.

Use this method to maximize the amount of GSHP run-time by allowing it to operate with supplemental heat when its heating capacity alone is not sufficient. This method assumes the system will switch over to dual fuel only when required by the utility provider. Remember, when the dual fuel system activates, the GSHP must be turned off.

Dual Fuel Override: Choose this method if a furnace or boiler will be used for auxiliary heat in a way which the GSHP will turn off and the dual fuel system (furnace or boiler) will activate when supplemental heat is required or when controlled based on outdoor air temperature. For water-air systems, this option eliminates the use of supplemental heating with electric resistance.

Use this method if all backup (second stage for single-capacity equipment or third stage for dual-capacity equipment) is to be supplied by the dual fuel system. Remember, when the dual fuel system activates, the GSHP must be turned off.

Back-Up System Type: Specify the type of furnace or boiler to be used for the dual fuel system.

AFUE: Enter the efficiency of the selected dual fuel system.

Control Based On

Hours of Operation: Select this option if you know the number of hours (on average) of dual fuel operation that will occur during the heating season. If you enter the hours of dual fuel operation, LoopLink will calculate the outdoor air temperature where the switch will be made.

Outdoor Air Temperature: Select this option if you know the outdoor air temperature where dual fuel operation will be required. If you enter the outdoor air temperature where the system will switch over to dual fuel operation, LoopLink will calculate the annual hours of operation for the dual fuel system.

For Dual Fuel Override systems, because the dual fuel system will be relied upon for supplemental heating, if the specified hours of operation correspond to an outdoor air temperature that is LESS THAN the balance point temperature for the zone, then the balance point temperature will be used to determine hours of operation instead. Balance point temperature is displayed in INSTALLED CAPACITY CHECK section.

Correction Factors

Account for variation in equipment performance when placed in conditions that differ from the manufacturer's rated conditions. Equipment performance is most affected by the temperature of the air entering the air-refrigerant coil (EAT), the air flow rate through the system (CFM), the temperature of the water entering the water-refrigerant coil (EWT), and the water flow rate through the system (GPM).

Show Correction Factors Click on the Down Arrow ( Down Arrow ) to show the GSHP correction factors (the default value for each correction factor is 1.000 - edit as necessary).

Hide Correction Factors Click on the Up Arrow ( Up Arrow )to hide the GSHP correction factors. Even when hidden, correction factors will be applied to the zone.

Heating Capacity: The correction factor that accounts for heating capacity variation when equipment is placed in conditions that differ from rated (different EAT, CFM, EWT, or GPM).

Heating Demand: The correction factor that accounts for heating demand variation when equipment is placed in conditions that differ from rated (different EAT, CFM, EWT, or GPM).

Total Cooling Capacity: The correction factor that accounts for total cooling capacity variation when equipment is placed in conditions that differ from rated (different EAT, CFM, EWT, or GPM).

Sensible Cooling Capacity: The correction factor that accounts for sensible cooling capacity variation when equipment is placed in conditions that differ from rated (different EAT, CFM, EWT, or GPM).

Cooling Demand: The correction factor that accounts for cooling demand variation when equipment is placed in conditions that differ from rated (different EAT, CFM, EWT, or GPM).

For a discussion on the following topics, refer to the pages in IGSHPA's Ground Source Heat Pump Residential and Light Commercial Design and Installation Guide as listed below:

  1. General discussion about correction factors: Section 2.5.3 (Chapter 2, page 48).
  2. Entering air correction factors: Section 2.5.3.1 (Chapter 2, starting on page 48).
  3. Air flow rate (cfm) correction factors: Section 2.5.3.2 (Chapter 2, starting on page 54).
  4. Antifreeze correction factors: Section 2.4.3.3 (Chapter 2, page 36).

Installed Capacity Check

Compare the installed capacity of the equipment to the zone loads.

Heating Mode

Heating Capacity: The heating capacity of the selected equipment at the specified minimum entering water temperature (EWT) and for the given entering air temperature (EAT), air flow rate (CFM), and water flow rate (GPM).

% Sizing: Heating capacity divided by the peak heating load for the space. A number greater than 100% indicates that the GSHP equipment has enough heating capacity to maintain the thermostat set point without supplemental heating during peak conditions. A number less than 100% indicates that supplemental heating will be required whenever space load exceeds the installed heating capacity.

% Energy From Geo: The percentage of the total heating energy required by the space that is provided by the geothermal. Use this number with % Sizing to find a heat pump that minimizes heat pump size while maximizing the amount of heat energy provided by the geothermal system without supplemental or dual-fuel back up.

Installed COP (Coefficient of Performance): The efficiency of the selected equipment at the specified minimum entering water temperature and for the given entering air temperature, air flow rate, and water flow rate. COP is defined to be heating capacity (Btu/hr) divided by electrical demand of the equipment (Btu/hr).

For more information on GSHP performance in the heating mode, refer to Section 2.2.1 (Chapter 2, starting on page 4) in IGSHPA's Ground Source Heat Pump Residential and Light Commercial Design and Installation Guide.

Balance Pt. Temp: The outdoor air temperature where heat pump capacity will not be sufficient to provide 100% of the building's heating requirements and supplemental (backup) heat is required.

Cooling Mode

Total Cooling Capacity: The total cooling capacity of the selected equipment at the specified maximum entering water temperature (EWT) and for the given entering air temperature (EAT), air flow rate (CFM), and water flow rate (GPM).

Sensible Cooling Capacity: The estimated sensible cooling capacity of the selected equipment at the specified maximum entering water temperature and for the given entering air temperature, air flow rate, and water flow rate.

% Oversizing: Sensible cooling capacity minus sensible cooling load divided by sensible cooling load. A number greater than 0% indicates that the GSHP equipment has enough cooling capacity to maintain thermostat set point at peak conditions. A number less than 0% indicates that the equipment is undersized in sensible cooling capacity and the next largest GSHP unit should be selected for the space. Typically, % over-sizing in the cooling mode should be no more than 25%.

Installed EER (Energy Efficiency Ratio): The efficiency of the selected equipment at the specified maximum entering water temperature and for the given entering air temperature, air flow rate, and water flow rate. EER is defined to be total cooling capacity (Btu/hr) divided by electrical demand of the equipment (W).

For more information on GSHP performance in the cooling mode, refer to Section 2.2.2 (Chapter 2, starting on page 6) in IGSHPA's Ground Source Heat Pump Residential and Light Commercial Design and Installation Guide.

Zone Operating Summary

View the GSHP equipment operating runtimes and associated energy usage estimates.

Heating Mode

Low-CAP Runtime: The number of hours of low-capacity operation in the heating mode for one year. For single capacity equipment, this term is hidden and defaults to zero.

High-CAP Runtime: The number of hours of high-capacity operation in the heating mode for one year.

Supplemental Runtime: The number of hours of supplemental resistance heat operation (if necessary) in the heating mode for one year.

Dual Fuel Runtime: The number of hours of dual fuel system operation (if necessary) in the heating mode for one year.

Heat Pump Energy Use: The amount of electricity consumed while operating the GSHP unit in the heating mode for one year.

Supplemental Energy Use: The amount of electricity consumed while operating the supplemental resistance heat in the heating mode for one year.

Dual Fuel Energy Use: The amount of energy consumed while operating the dual fuel system in the heating mode for one year.

Pumping Energy Use: The estimated amount of electricity consumed while operating the circulating pumps in the heating mode for one year.

Cooling Mode

Low-CAP Runtime: The number of hours of low-capacity operation in the cooling mode for one year. For single capacity equipment, this term is hidden and defaults to zero.

High-CAP Runtime: The number of hours of high-capacity operation in the cooling mode for one year.

Heat Pump Energy Use: The amount of electricity consumed while operating the GSHP unit in the cooling mode for one year.

Pumping Energy Use: The estimated amount of electricity consumed while operating the circulating pumps in the cooling mode for one year.

Zone Load and Operating Profile Graph

The Zone Load and Operating Profile Graph can be displayed or hidden by clicking the View Graph/ View Data buttons respectively.

For a full overview of the graph please see GeoConnected: Warning Graphic Geothermal Content

GSHP Operating Cost Breakdown

View the calculated costs to operate the GSHP equipment for the zone for one year.

Heating Mode

HP Operating Cost: The cost to operate the GSHP unit selected for the zone in the heating mode for one year. This calculation is based on the zone loads, capacity and efficiency of the selected equipment, the cost of electricity and the climate for the geographical location.

Supplemental Cost: The cost to operate the zone supplemental resistance heating elements (if necessary) in the heating mode for one year. This calculation is based on the zone loads, capacity and efficiency of the selected equipment, the cost of electricity and the climate for the geographical location.

Dual Fuel Cost: The cost to operate the zone dual fuel system (if necessary) in the heating mode for one year.

Pumping Cost: The estimated cost to operate the zone circulating pumps in the heating mode for one year. This calculation is based on equipment run-time and the cost of electricity.

Total Cost: The total cost to operate the GSHP equipment for the zone in the heating mode for one year, including the cost to operate the GSHP unit(s), the resistance heating elements, and the circulating pumps.

Cooling Mode

HP Operating Cost: The cost to operate the GSHP unit selected for the zone in the cooling mode for one year. This calculation is based on the zone loads, capacity and efficiency of the selected equipment, the cost of electricity and the climate for the geographical location.

Pumping Cost: The estimated cost to operate the zone circulating pumps in the cooling mode for one year. This calculation is based on equipment run-time and the cost of electricity.

Total Cost: The total cost to operate the GSHP equipment for the zone in the cooling mode for one year, including the cost to operate the GSHP unit(s) and the circulating pumps.