13 Making Geothermal Mainstream Geoener 2012

Making GeoExchange™ mainstream

III CONGRESO de Energia Geotermica en la EDIFICACION Y LA INDUSTRIA Slide 1

Ed Lohrenz, B.E.S., CGD

[email protected]

Member:

ASHRAE

GICC

MGEA

IGSHPA


III CONGRESO de Energia Geotermica en la EDIFICACION Y LA INDUSTRIA Slide

Decision to install GeoExchange system based on economics

2

Building owners and developers make their decision to install a geothermal system

based on money. A potential geothermal project that doesn’t show a good return on

your client’s investment will probably not be built.

A client may want to be “green”, but they won’t accept a 25 year payback to be “green”.

It’s almost always about the economics.



Public policy and the economics of GeoExchange systems

3

Governments and utilities have promoted GeoExchange systems with a variety of

policies, including:

• Cash incentives

• Financing / leasing

• GeoExchange utilities



Incentives and subsidies

4



Incentives or subsidies

5

Cash incentives are simple. Install a heat pump and get a rebate from the government

or utility. They are:

• Easy to administer – install a system & get money

• Expensive – incentives cost government (tax payers) a lot of money

• Inconsistent – governments change / policies change and confuse stakeholders in

the industry



Incentives or subsidies - experience in Canada

6

The recent experience in Canada with the ecoENERGY grant has not been positive.

The incentives were put in place, then taken away for several months, reinstated, and

then removed a few months earlier than was originally stated.

Approximately $100,000,000 was allocated for incentives, and it resulted in an

estimated 16,000 installations.



Incentives or subsidies – impact on the industry

7

The “on again, off again” nature of the incentives caused problems in the Canadian

industry. Sales increased as incentives were introduced, but dropped when removed.

Manufacturers, distributors and contractors reported of problems with inventory and

keeping trained employees as sales increased and decreased as incentives were put in

place, then taken away, then reinstated. It is not inconceivable that sales would be

greater in 2012 if the incentives had not gone through the changes the previous years.

Sales estimates

without incentives



Financing or leasing

8



Financing / leasing

9

The initial cost of a GHX is a market barrier. Financing or leasing by private investors,

utilities or government agencies provides a method of eliminating the cost barrier. To be

effective:

• The project must show a reasonable return on investment

• The financing term must be long enough to provide a positive cash-flow

• Private investors tend to want to finance larger projects – not residential



Financing / leasing

10

A GeoExchange system is usually more expensive to install than a conventional

mechanical system. Property Assessed Clean Energy (P.A.C.E.) allows property

owners (residential or commercial) to finance energy efficiency projects and:

• Repay it through an assessment on property tax for up to 20 years

• Repayment obligation transferred to next owner if property sold

• For more info, see: http://pacenow.org/blog/pace-one-page-primer/

http://pacenow.org/blog/pace-one-page-primer/











Financing or leasing

11



GeoExchange utilities

12

Electric utilities make large capital investments to produce power and deliver it to their

customers. They expect return on their investment over time as customers pay their

utility bills.

The benefit to the customer is that he does not have to make the investment to build the

generating station or infrastructure. The utilities make money on their long-term

investments.



GeoExchange utilities – under construction in Gibsons, BC

13

The community of Gibsons, BC is building a district geothermal energy system for 750

homes and a commercial development. The system uses horizontal GHX modules

combined with heat recovery from an ice arena and energy from the ocean as energy

sources. It will be completed in about 15 years, and is designed to grow with the

community.

Phase

1

Future phases

Future phases

Commercial

development

Hockey rink &

commercial

development

Ocean

connection

Ocean –

50-55F

year round



GeoExchange utilities - stakeholders

14

The Town built and operates the GHX and pump house. The developer installs the

distribution piping under the street. Ownership of distribution piping is transferred to the

Town. The home builder/owner is responsible for connecting the heat pump to the

system.

The Town invoices homeowners for energy transferred to and from the GHX.

The Town built

the GHX and

Pump house

Home builder /

home owner responsible to

connect to

distribution piping

Developer responsible for

construction of

distribution piping



GeoExchange utilities - typical home heat pump connection to district system

15

Piping connects the distribution piping to the individual homes. An energy meter

calculates the energy extracted from or rejected to the GHX. The meter information is

read via a radio transmitter and an “geothermal utility” bill is sent to the homeowner.



GeoExchange utilities - infrastructure for GeoExchange system

16

The GHX modules are built in park areas and greenbelts in the community. Piping to

connect the GHX modules to the pump house and then to the homes is installed by the

developer like any other utility.



GeoExchange utilities – homeowner benefits with lower monthly costs

17

Ultimately the homeowner pays for the GHX. The Town of Gibsons as the owner of a

geothermal utility, charges the homeowner a monthly fee for the energy and recovers its

investment, just like an electric utility building a generating station.

Like any other utility, the Town meters and charges for energy taken from or rejected to

the ground.

GeoExchange™ Gas Electric

Electricity

Cost

Geo utility

bill

Total Energy

Cost

Total Gas

Cost

Total Electric

Cost

Single $981 $948 $1,929 $2,275 $2,906

Cluster $342 $264 $611 $719 $860

Cottage $462 $372 $836 $984 $1,188



Conventional system cost

18

The cost to install a typical conventional heating and cooling system in a 250 m2 home

in Spain is estimated at about 15.000 €



GeoExchange system

19

If the GHX is not included, the equipment for a GeoExchange system can be installed

for about 18.000€

If connecting to a GeoExchange utility system, the cost difference is minimal.



GeoExchange utilities – homeowner sees little additional capital cost

20

For the GeoExchange utility, there is little difference in cost to the homeowner if they

install a conventional system or a GeoExchange system. They see about a 10% to 15%

energy cost reduction with minimal increase in capital cost.

CO2 reductions in the development are approximately 1,440 tonnes annually

High Efficiency Gas System GeoExchange™ System

Dist.

System

Furnace

& AC

Total

Cost

Connect

to GHX

Dist.

System

Heat

pump

Total

Cost

100 m2 5.000€ 5.000€ 10.000€ 500€ 5.000€ 8.000€ 13.500€

150 m2 7.500€ 8.000€ 15.500€ 500€ 7.500€ 10.000€ 18.000€

200 m2 10.000€ 10.000€ 20.000€ 500€ 10.000€ 12.000€ 22.500€



Design process

21



Design process for conventional HVAC system

22

The design process for a conventional heating, ventilation and air conditioning system

is pretty straightforward. The size of the gas line and cooling tower is simply based on

the peak heating and cooling loads of the design heating and cooling days.

Rooftop units and other conventional systems have been around a long time. You don’t

have to prove they work, and it doesn’t really matter if they have a bit more capacity

than needed. No one gets sued for oversizing!

Cooling tower

capacity specified

Size of gas line based

on peak heating load



Design for geothermal system requires more detailed analysis

23

Detailed hour by hour energy model of a building is the only way to determine:

• Peak heating & cooling loads

• Monthly heating & cooling energy loads

• Provides numbers to determine energy balance between heating and cooling

An accurate energy model allows you calculate energy cost & size and cost of

GHX…and payback.

As the designer of the

energy source you have to

know the long term

performance of the system



Designing a geothermal system is somewhat like designing a heating system for a

building in a remote community where fuel can only be delivered once a year.

The designer needs to know how much energy the building will need over the entire

year to determine how big a storage tank is required. Calculating annual energy loads is

the only way to accurately determine this. This requires a detailed hour by hour load

calculation with appropriate occupancy, lighting and ventilation scheduled.

The ground is not an infinite energy supply



Design process for GeoExchange systems

25



Design case study

26



Economics is affected by design

27

The designer of a GeoExchange system can have a large impact on the cost of building

it. Working with the architect, engineers and rest of the design team, the heating and

cooling loads can be adjusted to work most efficiently with a ground heat exchanger.



Initial energy loads provided for project

28

The client provided initial peak and annual energy loads for the project. The loads

showed the building to be very cooling dominant with peak cooling loads of over 4,000

kW and peak heating loads of 3,500 kW.



GHX model based on initial loads provided

29

The GHX for the project based on provided loads cannot be sustainable over the long

term, even with 91,000 m of drilling. After approximately 10 years the maximum

temperature of the entering water temperature to the heat pumps exceeds 40°C.

Cost of GHX at 50 € / m: 4 550 000 €



GHX model based on initial loads provided with addition of fluid cooler

30

Adding a fluid cooler to dissipate excess heat from the building reduces the amount of

drilling required for the project by about 67%.

Cost of GHX at 50 € / m: 1 500 000 € plus cost of fluid cooler



Initial energy model for project

31

A detailed hourly energy model was completed for the building. The client provided

detailed information about the building, including:

• Occupancy (hourly / weekly)

• Lighting schedules

• Ventilation schedules

Peak loads and annual energy loads were much lower than model provided by client.



GHX based on first energy model

32

The GHX was recalculated with the new energy model. The amount of drilling required

was 70% less than needed with the original energy model and 10% less than needed

with the original loads with a cooling tower. The temperature of the GHX still keeps

increasing over time and will eventually fail.

Cost of GHX at 50 € / m: 1 368 000 €



Changes made to reduce cooling loads

33

During design charette cooling loads were reduced when information about the energy

model was provided to the architectural and electrical engineering teams.

• Lighting was reduced from 2.25 Watts / square foot to 1.25 Watts / square foot

• Roof was changed to reflective white material

Peak heating loads were not impacted, but annual heating energy loads increased from

129,279 mWh to 159,944 mWh because less heat was contributed by lighting.



Ice storage added to reduce peak cooling loads

34

Ice storage system designed to provide 790 kW of cooling for approximately 8 hours

per day. This reduces the capacity of equipment needed to provide peak cooling, yet

still provides all of the heating for the building.

Energy storage allows client to take advantage of peak electrical demand reduction,

demand shifting and time of use electrical rates.



Additional cooling loads from the building

35

Refrigeration for a 600 seat restaurant, a computer server room and elevator equipment

room were all tied into the GHX rather than roof-mounted air cooled condensers.



Dissipating excess heat

36

To prevent the GHX from overheating over time, a method of getting rid of excess heat

was still required. A cooling tower could have been added.

Instead 3,500 m2 of snow melt piping was added to the ramp to the parking level and

loading dock area. This can also be used to pre-cool the GHX all winter to “store” cold

in the ground.



Final energy model based on changes to building & systems

37

Changes to the building and systems made significant changes to the building energy

profile…and the

• Peak and annual energy cooling loads reduced by changes to roof & lighting

• Peak cooling loads reduced by integrating ice storage

• Cooling loads to GHX increased by additional refrigeration loads

• Heating load from GHX increased by snow melt / heat dissipation



Final energy model based on changes to building & systems

38

Decreasing cooling loads while increasing heating loads balances the energy loads to

and from the GHX. This results in a much smaller GHX. Using the snow melt / heat

dissipation to cool the ground lets us control the GHX temperature and prevent it from

becoming saturated with heat over time.

Cost of GHX at 50 € / m: 988 000 €



Peak load summary of successive energy models

39

The peak loads were reduced significantly when an actual energy model was built. The

goal during the succeeding iterations was first to reduce peak loads to the ground, and

more importantly, to balance the loads. Working with the client & design team allowed

the changes to the roof, lighting, mechanical system and snow melt.

Peak cooling loads are 2 to 3 times greater than peak heating loads without the artificial

heating load imposed by the snow melt/heat dissipation system.



Energy load summary with successive energy models

40

The heat rejection capacity of the snow melt / heat dissipation pad helps control the

temperature of the GHX, and is used to prevent the GHX from overheating over time.

Without the artificial heating loads imposed by the snow melt/heat dissipation system

the annual cooling energy loads are approximately 10 times greater than the annual

heating energy loads, not including the electrical energy used to operate the

compressors and pumps.



Drilling required with successive energy models

41

The total amount of drilling required for the building changed significantly as the energy

model developed and the design team made changes to the building.

The land area needed for construction of the GHX must be considered. The boreholes

for this project were drilled under the building. There was not enough space on the site

to build the original GHX with 600 boreholes.



Capital cost of ground heat exchanger with successive energy models

42

The cost of the GHX is typically the difference in cost between a conventional HVAC

system and a geothermal system. As the size of the GHX drops the cost drops.

In an integrated design process there are many implications to the cost of the project.

The cost of ventilation energy recovery, redesigned lighting, white roof, energy storage,

snow melt etc. must be considered in the payback, and are included in this analysis.



Energy cost saving and simple payback of system based on successive models

43

The total amount of drilling required for the building changed significantly as the energy

model developed and the design team made changes to the building.

The financial model must work for the client. Reducing size and cost of the GHX,

improving system efficiency and providing additional benefits helps make it happen.



Conclusions

44

• INCENTIVES – influence the market – but must be consistent

and well thought out or suppliers and contractors can be

adversely affected.

• FINANCING AND LEASING – reduces first cost for end user.

• Private investors typical prefer to finance large projects.

• Local governments or utilities can facilitate the finance

single residential projects

• GEOEXCHANGE UTILITY - owns the ground heat exchanger.

Cost of equipment inside the home is same cost as a

conventional system

• DESIGN PROCESS needed for GeoExchange system is

different than the design process for a conventional system

• The designer has the power to change the energy loads of

a building to make it more cost-effective to install a

GeoExchange system



Ed Lohrenz, B.E.S., CGD

[email protected]

Member:

ASHRAE

GICC

MGEA

IGSHPA

13 Making Geothermal Mainstream Geoener 2012

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