Aspects concerning the comparison of the apartments management costs in case various heating systems are used.

Ignaton, Elemer ; Cociu, Nicolae ; Oana, Tiberiu 等

1. INTRODUCTION

Before 1989, in Romania, the only heating source for the block-of-flats apartments was the central heating, either from the district heating points, or from thermal stations and heating point's adherent to the block-of-flats districts. Their heating efficiency at the most was under 50 %, and the heat losses from the thermal station to the heating points and from here to the blocks-of-flats were substantial.

In order to improve the efficiency of the thermal stations and to reduce the heat losses on the distribution pipes directions, expensive investments were necessary which partially solved these problems. Consequently, further funds are required for the updating of the thermal stations, of the heating points, for replacing the old pipes for heat carrier distribution with previously isolated pipes.

A heat metering program for the blocks-of-flats has been initiated, to enable the beneficiaries pay as much as they use (without distribution losses). Thus, in most of the big towns the heat metering has already been completed.

On account of the high costs of the central heating, there appeared a heating alternative, namely with thermal stations for apartments with solid fuel or with natural gases (pit gas).

At present, there are many different opinions concerning the efficiency of the above mentioned systems.

This paper tries to present various aspects making the comparison of the total maintenance costs for an apartment heated by means of a centralized heating system, with an apartment thermal station with pit gas.

2. THE COSTS COMPARATIVE CALCULATION

The costs comparative calculation has been made for an apartment in a block-of-flats having three rooms with separate doors, of 1 type confort, Cb3. The apartment have: entrance hall, kitchen, 2 bedrooms, dining room, bathroom, toilet, balcony and logie, presented in figure 1.

The block-of-flats apartment are the following characteristics:

* Built surface : [S.sub.c] = 80.74 [m.sup.2];

* Useful surface : [S.sub.n] = 66.35 [m.sup.2];

* Granulite concrete external walls: A3b type;

* Number of persons: 3 persons.

2.1 Total management costs--centralized heating

In this case the heat carrier for the apartment heating is supplied from a heating point (PT 32), and the monthly management costs are presented in table 1, being taken from the table with the block-of-flats expenses. Mention should be made that since 1980, when the apartment was commissioned by the builder and the year 2001, when the apartment thermal station was put into operation, the rooms temperature was not higher than 18[degrees]C (frequently 16 - 17[degrees]C).

[FIGURE 1 OMITTED]

2.2 Total management costs--apartment thermal station

In March 2001, the centralized heating was replaced with the apartment thermal station--the new investment for the apartment own heating with pit gas.

2.2.1 The costs of investment

The investment costs comprise costs for the common part and for one's own works in the apartment.

The following costs were required for the investment:

a). Common parts: design for the gas installation, gas installation--in the staircase, gas controller--gas:

Total: 1.940.000 ROL, 194 RON = 65 $.

b). Own works--in the apartment: gas installation--in the apartment, heating installation/hot water, thermal station Vaillant of 24 W, manual thermostat:

Total: 40.500.000 ROL

4.050 RON = 1.360 $.

General total: 42.440.000 ROL,

4.244 RON = 1.425 $.

In thes case the total investment is:

[I.sub. tot]. = 4.244 lei (1.425 $).

Mention should be made that the exchange rate leu/$ at that time was of 2,970 RON for a dollar.

2.2.2 Costs for the apartment management

For example, table 1 presents the costs for the apartment management deducted according to the different categories of expenses for 2006:

* common parts expenses (cold water, sewerage, electric energy in the staircase, caretaker, repairs, etc.);

* own expenses (the cost of the pit gas consumption).

The own expenses did not take into account the costs of the electric current consumption for the operation of the thermal station, due to the fact that these expenses remained the same after the thermal station mounting.

After the analysis of the data from figure 1, there result savings, as far as the expenses are concerned, of E = 702.2 lei for a period of 5 year.

The investment recovery ([R.sub.i]) under the previously presented conditions can be accomplished in:

[R.sub.sub.i] = [I.sub.tot]/E 4.244 lei/702 2 lei = 6,04 yeare (1)

3. CONCLUSIONS

According to the studies and calculations presented in table 1/figure 1, there result the following conclusions:

* The use of the apartment heating station with pit gas results in an average economy of the expenses for 5 years at the apartment management of E = 702.2 lei/year;

* The consumer pays exactly what has been consumed;

* The consumer decides what is the needed temperature in the apartment;

* The consumer starts and stops the heating station when necessary.

* The initial investment is big, but it is recovered in 6,04 year.

Thus, it can be concluded that the use of the gas thermal stations for the apartments heating results in the reduction of the apartment management expenses and stands for a feasible alternative bringing important annual savings.

4. REFERENCES

Ignaton, E. (1996). Management si marketing, Management and marketing, Editura EUROBIT, ISBN 973-9201-75-X, Timisoara

Ignaton, E. (2009). Ingineria organizarii santierelor de constructii, Site engineering, Editura POLITEHNICA, ISBN 978-973-625-846-6, Timisoara

Project Nr. 23164/180, (1979) "Proiect bloc de locuinte, Project for block-of-flats", Timisoara

Project Nr. 1L01/02, (2001). Alimentare gaze naturale imobil, contorizare/apartament--instakatie comuna, Building natural gases supply, metering/apartment--common installation, Timisoara

Project Nr. 1L01/03, (2001). Alimentare gaze naturale imobil, contorizare/apartament--Instakatie proprie ap. 10, Building natural gases supply, metering/apartment--common installation and own installation, ap.10, Timisoara

* * * * Cheltuieli lunare de la Asociatia de locatari perioada 2004-2008, Monthly expenses from the Owners' Association within 2004-2008

Tab. 1. Costs for apartment management

 Own expenses (lei):

Consumption Common Total
 period parts Gas cost expenses
 2006 (lei) (lei) (lei)

January 51,88 267,10 318,98
February 32,29 259,52 291,81
March 48,26 204,58 252,84
April 46,58 80,03 126,61
May 66,69 41,50 108,19
June 43,12 46,43 89,55
July 37,12 34,11 71,23
August 46,77 32,11 78,88
September 64,29 40,13 104,42
October 49,65 64,20 113,85
November 55,84 207,24 263,08
December 59,43 293,82 353,25
 601,92 1570,77 2172,69

 Similar apartment expenses
 (lei)

Consumption Common Total Economy
 period parts Gas cost expenses [+ or -]
 2006 (lei) (lei) (lei) (lei)

January 361,85 5,96 367,81 -48,83
February 299,69 6,29 305,98 -14,17
March 343,79 5,02 348,81 -95,97
April 245,61 8,03 253,64 -127,03
May 286,99 9,27 296,26 -188,07
June 205,59 6,20 211,79 -122,24
July 202,28 8,03 210,31 -139,08
August 167,39 8,13 175,52 -96,64
September 239,63 6,20 245,83 -141,41
October 136,56 5,02 141,58 -27,73
November 206,91 7,59 214,50 48,58
December 296,51 13,01 309,52 43,73
 2992,80 88,75 3081,55 -908,86

Fig. 2. Comparison costs and economies
 2004 2005 2006 2007 2008

Own expenses 1081 1559 2173 2370 2593
Similar apartment
 expenses 1718 2309 3082 2861 3316
Economy 637 750 910 491 723
Economy Average
 for 5 yeare 702,2 702,2 702,2 702,2 702,2

Note: Table made from line graph.