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Layman’s Report

Supermarket retrofit for zero energy consumption (LIFE12 ENV/ES/000787)

www.lifezerostore.eu

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Supermarket retrofit for zero energy consumption (LIFEZEROSTORE) - LIFE12 ENV/ES/000787

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GOAL AND SCOPE OF THE

PROJECT

The main objective of this project is to

demonstrate the technical and economical

feasibility of an innovative integral highly

reliable solution for supermarket retrofitting

to make them auto sufficient from the

energy point of view.

In a conventional supermarket almost 70%

of energy is used for cold production by

electric compressors. LIFEZEROSTORE

project develops an innovative system

based on the combination of three very

different technologies working together:

biomass, absorption and co-generation, all

together receiving the name of trigene-

ration. This, along with other energy saving

measures, makes this supermarket the

first store aimed at energy self-

sufficiency.

This integral solution will allow savings

between 60 to 65% of electric energy and

avoid a high percentage of the energy

purchased from the electric network.

Applied in other stores and supermarkets in

Europe, a reduction of up to 3% of the

electricity consumption in Europe was

initially estimated according to the most

theoretical case.

Consortium:

• EROSKI S. Coop.: First retailer group ofthe cooperative type in Spain.

• CENER-CIEMAT Foundation: Techno-logical centre specialized in solutionsbased on renewable energies.

• L Solé, S.A.: Leader company inbiomass plants.

• Expander Tech S.L.: Specialists incogeneration systems.

• Ipar Hotz S.L.: Specialists in theinstallation and maintenance of industrialcold systems.

Duration: Del 2013/07/01 al 2017/06/30

Budget: 1.924.479 €

Funding LIFE+: 887.239 € (50% budget)

Location: Vitoria-Gasteiz, Spain (Fig.1)

THE WAY TO THE

LIFEZEROSTORE

The commitment of EROSKI with sustaina-

ble development implies improvements of

the design and execution of our activities in

order to ensure the preservation of the

environment. This commitment is inte-

grated across the whole organization by

our Environmental Policy. Among the work

lines derived from it is the implementation

of sustainable construction criteria in our

stores. The progress achieved in this area

during the past years led us to start the

LIFEZEROSTORE project in 2013.

2008

2009

2010

2011

2012

2013

A global environmental risk and

impact map and a guide about

sustainability construction were

created.

Pilot tests to check the improvement

measures previously identified were

conducted with satisfactory results.

ECOEFFICIENT STORE of Gros

(Gipuzkoa), with between 15 and

20% less energy consumption than

a conventional store.

ECOEFFICIENT STORE of Castro

(Cantabria), with improvement

measures and energy savings

similar to the store in Gros.

ZERO EMISSIONS STORE of

Oñate (Gipuzkoa), the first in the

Spanish State with BREEAM

(Building Research Establishment

Environmental Assessment Metho-

dology) sustainable construction

certification and the first in Europe to

obtain energy management certi-

fication ISO 50001. It is a zero CO2

emission store thanks to green ener-

gy purchase and the incorporation of

energy efficiency measures and

sustainable construction criteria,

which led to the achievement of

60% saving in energy consumption

in comparison to a conventional

centre.

LIFEZEROSTORE project starts in

Vitoria-Gasteiz (Araba).


3

Vitoria-Gasteiz(Basque Country,Spain)

Fig. 1. Location of the LIFEZEROSTORE

METHODOLOGY, ARCHITEC-

TONICAL AND TECHNOLO-

GICAL SOLUTIONS AND

INTEGRATION

A trigeneration system based on

biomass was installed in the supermarket

“EROSKI Center” of Ali-Gobeo (Vitoria-

Gasteiz). The biomass is provided by local

sawmill companies which generate as

residue splinter of wood certified by PECF

(Programme for the Endorsement of Forest

Certification). The splinters are burned in a

boiler, thus heating oil to a temperature

between 180 and 205ºC. The heat from this

oil is used by a Organic Rankine Cycle

(ORC) to generate electricity, as well as

two circuits of hot water as by-product: one

at medium-to-high temperature and other at

medium-to-low temperature. The resulting

ashes from the biomass are used as

fertilizer in agriculture.

The water from the medium-to-low

temperature circuit exists the ORC at 50ºC

and it is used for heating the supermarket.

This is possible thanks to the heat exchan-

gers placed in the air handling units. When

there is extra heat available after heating

the store, the water circulates through a

heat dissipater located on the roof.

On the other hand, the heat of the water

from the medium-high temperature circuit

leaves the ORC at 88ºC. This heat is used

by an absorption machine of Lithium

Bromide (LiBr), which subcools the

condensation of the positive cooling plant.

The previous negative cooling plant with

R404A which condensed outside was

substituted by a CO2 refrigeration system

which condenses against the positive

cooling plant. Moreover, the refrigerant of

the positive cooling plant was also

substituted by another one with lower

environmental impact. This is possible

thanks to the combination of a zero ozone

depletion potential, a lower global warming

potential and a high energy efficiency.

Figure 2 shows an schematic diagram of

the integration of the different systems that

was carried out.

Fig. 2. Schematic diagram of the trigeneration system installed in the LIFEZEROSTORE

4


4

All this equipment was installed in a

flexible way guaranteeing the feasibility of

a later extension to future facilities.

Before selecting the solution described, an

in-depth assessment of the different

proposed technologies and the feasibility

of their integration into a trigeneration

system adapted to the needs of a

supermarket was conducted. Among other

considerations, the location choice, the

installation of systems for monitoring and

results analysis and the various options

possible for the integration of the systems

were reviewed.

The trigeneration system

provides a high percentage of

the energy necessary for the

cold for freezers and fridges,

the heat for climatization and

hot water and the electricity for

lighting and other uses

The trigeneration system was placed in a

way that it is opaque to the outside. This is

thanks to the building of a metallic structure

on the façade of the store covering the

equipment that supplies electric power,

climatization and commercial cold to the

supermarket. (Fig. 3).

Moreover, multiple energy efficiency

improvement measures were imple-

mented in the supermarket. Some of them

are:

• renovation of the lighting system by a

new one that adjusts the amount of light

provided depending on the levels of

ambient light in the room;

• placement of skylights on the roof to

allow the entry of solar light;

• installation of a glass structure at the

store’s main entrance to avoid the direct

entry of air; and

• removal of two “air curtains” (Joule

effect) installed over the entrance doors.

Fig. 3. Backside of the supermarket where the equipment of the trigeneration system is installed


5

RESULTADOS DEL PRYECTO

Evolution of the electric consumption

for climatization

Two “air curtains” installed over the

automatic access doors that heated air at

the entrance by Joule effect were removed.

They were substituted by a glass structure

of double doors that avoids the direct entry

of air from outside, as shown in Figure 6.

These improvements led to a saving in

electricity consumption for climatization of

16.63% (Figure 7).

*It should be taken into account that at the beginning of the

project (year 2013), the values recorded for the “roof-top”

equipment used for climatization were not correct. Thus, in the

graph presented in Figure 7, the values used correspond to the

consumption from the “air curtains” during the first year and from

the “roof-top” during 2016.

PROJECT RESULTS


for cold

At the beginning of 2016 the previous cold

production plant was replaced by a new

one including a cascade cooling cycle (Fig.

4). This directly affects the negative cooling

plant, which uses CO2 (R744) as refrigerant

and which condenses against the positive

cooling plant, which uses R450A (also

known as N13) as refrigerant. This allowed

a 75% size reduction of the negative

cooling plant and the removal of the

condensers in the negative cooling plant on

the roof.

With those modifications the efficiency of

the system increased, as the negative

cooling plant reduces considerably its

consumption of electric energy. Specifically,

the decrease was of 17.15% (Fig. 5).

Fig. 4. New negative cooling plant that uses

CO2 as refrigerant

Fig. 6. Glass structure with double doors that

avoid the direct entry of air from outside

Fig. 5. Evolution of the energy consumption for cold

Fig. 7. Evolution of the energy consumption for

climatization*

Rooftop 1

Rooftop 2

Curtain 1

Curtain 2

START END0

50.000

100.000

150.000

200.000

250.000

En

erg

y c

on

su

mp

tio

n[k

Wh

]

START END0

50.000

100.000

150.000

200.000

250.000

En

erg

y c

on

su

mp

tio

n [

kW

h]

300.000

350.000

Ice machine 2

Ice machine 1 Positive cold

Others

Lighting

Negative cold

6


6


for lighting

The improvement measures implemented

included the installation of expansive sky-

lights on the roof of the supermarket to get

more solar light into the inside of the store

(Fig. 8 y 9). In order to make the most of

that increase of solar light in the inside, the

existing lighting system using fluorescent

lamps was substituted by LED technology

with illuminance control.

Evolution of the electricconsumption for lighting

All these improvements generated a

reduction of 30.07% in electricity consu-

med for the lighting of the sales floor

during working days (Fig. 10).

*With the aim of avoiding an overestimation of the savings, the

year within the four time periods for which there is data available

chosen to be represented in Figure 10 corresponds to the

period between the 1st of September of 2014 and the 31st of

August of 2015. This is the period with values most similar to the

average consumption but lower than it.

After all the retrofitting, the share of the

energy consumption in the supermarket is

48.8% for cold production, 27.04% for

climatization and 13.3% for lighting.

The energy efficiency improvement measures reduced

23,57% of the total electric energy consumption thanks to savings of 17% in cold, 16% in

climatization and 30% in lighting

Fig. 8. Lighting system with expansive

skylights

Fig. 10. Evolution of the energy consumption

for lighting*

Fig. 9. Skylights on the roof of the supermarket

CONVENTIONAL SYSTEM

Limited amount of light Hot spots

LLEDÓ SUNOPTICS®

Solution

Backery lighting

Lockers lighting

Sales-floor lighting

Outside lighting

START END0

10.000

20.000

30.000

40.000

50.000

60.000

70.000

80.000

En

erg

y c

on

su

mp

tio

n[k

Wh

]


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scenario number 5 and 66,45% of scenario

1 is obtained (Fig. 12).

The trigeneration system

functioning the whole year

achieves the objective of 65%

reduction in electricity

consumed from the network

Reduction in greenhouse gas

emissions

The European Union has the goal of

reducing 40% greenhouse gas (GHG)

emissions in 2030 in relation to 1990. The

LIFEZEROSTORE project aims to facilitate

the fight against climate change too.

Therefore, the reduction of CO2 equivalent

emissions generated due to the daily

activity of the store was calculated.

In the calculation of the total global

warming impact two types of emissions

were taken into account: the direct

emissions due to refrigerant leakages and

the indirect emissions due to electricity and

biomass consumption. The latter could be

also included as direct emissions, but

those emissions were considered to be the

consequence of burning biomass to obtain

the final calorific energy needed.

Reduction in electricity purchased

thanks to the trigeneration system

Five use scenarios for the trigeneration

system were simulated with the tool

TRNSYS in order to estimate the electric

energy that is necessary to buy from an

electric company to fulfil all the needs of the

supermarket (Fig. 11). It was checked that

the ORC works in a very regular and stable

way, with an electricity yield between 10

and 11%. But to achieve a suitable yield of

the installation is critical to use the thermic

energy obtained as sub-product in the

ORC, as well as minimizing the energy

dissipation in the medium-low temperature

circuit. Therefore, the two variables

considered in the design of the scenarios

are:

• functioning period: the whole year, only

during heating season (7 months per

year), or depending on daily demand of

heating; and

• oil temperature at the ORC entry: fixed at

205ºC or variable between 180 y 205ºC

depending on the heating demand.

Considering as reference the typical energy

consumption in other supermarkets and

climates similar to the ones in the project

(824 MWh), an external electricity

consumption saving between 43,78% of

Fig. 12. Percentage reduction of the electricity

purchased to fulfil the energy needs of the

supermarket. Scenario number 0 corresponds

to the savings thanks to the implementation of

the energy efficiency improvement measures.

Fig. 11. Scenarios simulated to evaluate the

impact of the trigeneration system

Whole

year

Heating

season

Heating

daily

demand

205ºC

205ºC

Variable depending

on dissipation

205ºC

Variable depending

on dissipation

1

2

3

4

5

Functioning

periodOil temperature

Sce-

nario

24%

66%

54%

47% 46%44%

0%

10%

20%

30%

40%

50%

60%

70%

0 1 2 3 4 5

Re

du

ctio

nin

ele

ctr

icity

pu

rch

ase

d[%

]

Scenarios

8


8

Economic savings due to ZEROSTORE

The reduction in the electricity consum-

ption may imply not only a lower environ-

mental impact but also lower costs. For the

calculation of the economic savings, the

needs of biomass and of electricity from

the network in each of the scenarios

simulated were considered. The price of

biomass used corresponds to data from

April 2018 of the Spanish Association of

Biomass Energetic Valorization (Asocia-

ción Española de Valorización Energética

de la Biomasa, AVEBIOM). It is foreseen

that the maintenance costs will be included

in the biomass price.

Direct GHG emissions

For the calculation, the substitution of the

refrigerants used in the cooling plants by

others with a lower global warming

potential (GWP) was taken into account.

The GWP is a relative measure of the

heat trapped by a gas in comparision to

the amount trapped by CO2.

Moreover, the leakages of refrigerants

decreased from 8% to 5% during the

project. All these improvements led to a

reduction of 94,87% in GHG direct emis-

sions. This implies that the emissions of

202 tonnes CO2 eq. were avoided.

Indirect GHG emissions

The emission factor of biomass is also

much lower than the one of the electricity

(0,018 kg CO2 eq./kWh instead of 0,331

kg CO2 eq./kWh).

The indirect emissions also vary between

the scenarios presented in Figure 11 as

each of them has a different electricty

consumption from the network and

biomoss consumption in the boiler. Thus,

the reductions vary between 39,69% of

scenario 3 and 49% of scenario 1. In

absolute values correspond to a yearly

decrease in the emissions of 134 tonnes

CO2 eq.

Total GHG emissions

Thanks to the new trigeneration system

and the energy efficiency improvements

implemented, reductions between

63,91% (scenario 3) and 69,20%

(scenario 1) of total CO2 eq. emissions

are estimated (direct and indirect

emissions). That is, up to 336 tonnes

CO2 eq. per year could be avoided.

Fig. 13. Percentage GHG emissions reduction

for each trigeneration system functioning

scenario

Start End

Positive

cooling

plant

R404-A(GWP: 3.922

kg CO2 eq./kg)

R450-A(GWP: 547 kg

CO2 eq./kg)

Negative

cooling

plant

R404-A(GWP: 3.922

kg CO2 eq./kg)

CO2 (R744)(GWP: 1 kg

CO2 eq./kg)

Table 1. Refrigerants used with their global

warming potentials

0%

10%

20%

30%

40%

50%

60%

70%

80%

1 2 3 4 5

GH

G e

mis

sio

nre

du

ctio

n[%

]

Scenarios

Directas Indirectas

1 2 3 4 5

Fig. 14. Percentage economic saving depending

on the electricity price and the trigeneration

system functioning scenario

-50%

-40%

Ec

on

om

ics

avin

g[%

]

-30%

-20%

-10%

10%

20%

30%

40%

50%

Electricity price [€/kWh]


9

As shown in Figure 14, if an average

electricity price of 0,07€/kWh was consi-

dered, the trigeneration system would

generate economic savings in scenarios

3, 4 and 5. However, it would not be pro-

fitable when the system is functioning the

whole year or during the heating season

at 205ºC (scenarios 1 and 2).

Further analysis was conducted for sce-

narios 3, 4, and 5 in order to determine

the minimum ratio between electricity

and biomass prices that is economically

advantageous. According to this assess-

ment, the most profitable scenario is

when the trigeneration system works

depending on the daily heating demand

and with variable oil temperature (sce-

nario 5). In that case, it is necessary for

the trigeneration to be profitable that

the electricity kWh is at least 1,6 times

higher than the price of biomass kWh.

Scenarios 3 and 4 require ratios of at

least 2,7 and 1,9, respectively. Conse-

quently, the achievement of economic

savings due to the installation of the

trigeneration system is likely for the

scenarios considered, as long as the

energy prices are stable and reasonable.

IMPACT IN EROSKI AND

EUROPE

In order to estimate the possible environ-

mental and economic impacts derived

from the use of the trigeneration system

in other supermarkets, a simulation with

864 EROSKI supermarkets and 8.000

stores in Europe that have a sales floor

of more than 400 m2 was carried out.

The calculated savings depend not only

on the sales floor surface, but also on the

location, climatic zone or country where

the store is located.

Although it was proved that the objective

of 65% reduction of electricity purchased

from the network could be achieved

when the trigeneration system was

working the whole year (scenario 1), this

option resulted not as profitable as other

uses of the system more rational in the

simulation. Thus, scenario 5 was used

for calculating the impacts. This resulted

in the possibility of 310 Mill. € saving in

electricity purchased and 1,2 Mill. tn

CO2eq. avoided in Europe.

But those environmental and economic

benefits are not the only positive impacts

in case of replicability at National and

European level. The socioeconomic

impact due to the jobs created in the sec-

tors related to the installation and mainte-

nance of trigeneration systems and to the

retrofitting of stores to implement energy

saving measures should also be

considered. For instance, around 45.000€

are estimated per year only for the ope-

rative costs for maintaining the installation.

PROYECT DISSEMINATION

Additionally to the notice boards placed in

the store, press releases and the website

www.lifezerostore.eu, the project was also

presented in different international con-

ferences and via several articles pu-

blished in technical journals. The project

also caught the interest of business

organisations, such as the New Energy

and Industrial Technology Development

Organization (NEDO) from Japan.

EROSKI EUROPE

No. stores

considered864 8.000

Network energy

savings

43,5%

(220 GWh)

49,98%

(2.862 GWh)

Indirect GHG

emissions

savings

38,7%

(63.000 tn

CO2 eq.)

46,97%

(1,2 Mill. tn

CO2 eq.)

Economic

savings

26,9%

(17 Mill. €)

35,02%

(310 Mill. €)

Table 2. Environmental and economic impacts

of replicating the trigeneration system in other

stores according to functioning scenario no. 5

Fig. 15. Visit of NEDO to the ZEROSTORE

http://www.lifezerostore.eu/

This project is the first

step to reduce up to 3%

of electricity consumption

in Europe, in the most

theoretical case

Project name Supermarket retrofit for zero energy consumption (LIFEZEROSTORE)

Project number LIFE12 ENV/ES/000787

Location Vitoria-Gasteiz. Álava. Basque Country. Spain

Duration 4 years (from 2013/07/01 to 2017/06/30)

Budget 1.924.479 €

LIFE+ Funding 887.239 € (50% of the budget)

Website www.lifezerostore.eu

ContactEROSKI, S.Coop., Bº San Agustín, s/n, 48230 Elorrio (Spain)

Tel. +34 94 621 12 11. E-mail: [email protected]

http://www.lifezerostore.eu/

mailto:[email protected]

presentación de powerpoint€¦ · by an absorption machine of lithium bromide (libr), which...

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