**4. Summary and conclusions**

**Figure 7.** Simulated building temperatures for different types of plaster: clay mortar with a 15% of MPCMs, the standard

**Mortar Ti (°C) Tf (°C) Tma (°C) Map (J/g°C) Qlt (J/g) Cpm (J/g°C) TES (kWh/m3**

**Table 5.** Summary of the results obtained using DSC and the equipment prepared for the thermal characterization of the samples of clay mortar containing microcapsules at 5, 10, and 15% contents: master sample (MS), initial accumulation temperature (Ti), final accumulation temperature (Tf), maximum accumulation temperature (Tma), maximum accumulation point (Map), total latent heat (Qlt), average specific heat (Cpm) and thermal energy storage (TES).

MS — — — — 1.01 5.22 5% 15.63 31.26 23.57 1.77 2.87 1.28 5.71 10% 14.03 30.55 24.35 2.26 5.53 1.48 7.45 15% 11.10 30.65 24.39 3.07 10.59 1.53 8.62

162 Sustainable Buildings - Interaction Between a Holistic Conceptual Act and Materials Properties

**Table 6.** Summary of results obtained by simulating the energy demand using the HVAC (heating/ventilation/air conditioning) option for the different plaster types: clay mortar with a 15% microcapsule content, the master sample (MS), and gypsum mortars applied by a machine (Gap). Summer conditions (July 15–31); 15-day simulation periods, and a step size of less than a minute. Total simulation time: 408 h. Total energy at the site (TEsite), total energy from the source (TEsource), energy for the total building area at the site (ETBAsite), and energy per total building area at the

**) ETBAsource (kWh/m2**

**)**

**)**

sample (ecoclay) and a gypsum (Yeso). Summer conditions (July 15–31).

source (ETBAsource).

**Mortar TEsite (kWh) TEsource (kWh) ETBAsite (kWh/m2**

B. MSheating 593.58 626.63 5.28 5.57 B.15%heating 584.73 617.28 5.20 5.49 B. Gapheating 646.01 681.97 5.72 6.04 Despite the absence of regulated and agreed-upon rules for the characterization of clay-based mortars, it has been possible to propose a test methodology capable of establishing the technical feasibility of this construction material. Considering the nature of materials derived from crude earth and the descriptions in [19–27], the standard series used for mixing, molding and curing of clay mortars allows the comparative analysis of the results of different dosages.

The results of the fresh mortar tests have been used to evaluate the influence of incorporating a PCM on mixing and workability. One of the conclusions drawn is that the addition of a PCM requires the amount of mixing water to be increased to reach the established runoff values. These data show how the addition of a PCM supposes a decrease in the mortar's workability. Regarding the air content occluded in the mortar, it is observed that the microcapsules are deposited between the clay sheets, which increases the distance between them and increases the number of voids.

In the hardened state, the specimens show that the effects of retraction start to be considerable when the amount of the PCM reaches 10%. However, the response to this increase in retraction should be not to increase the amount of the PCM but to increase the amount of mixing water. This aspect should be analyzed using different clay mortar granulometries to improve workability by adding a PCM, thereby avoiding the increase in the amount of mixing water.

Clay-based products tend to perform well in terms of absorption capacity and water vapor permeability. The water vapor absorption capacity decreases as the number of microcapsules increases; however, the high hygroscopic capacity of clay means that all the samples, regardless of the amount of the PCM added, present better results than other conventional mortars, such as gypsum or cement and lime mortars. The permeability to water vapor follows the same trend as the absorption of water vapor, that is, it decreases as a PCM is added. This is due to the hydrophobic character of PCM microcapsules.

The results of the flexion-compression tests show a decrease in strength in both cases; this is more significant in compression (53.5% with respect to the standard dosage) than in flexion (45%) for the sample containing 5% PCM. The decrease in strength experienced with the first addition of the PCM is justified by the loss of density of the material due to the incorporation of the PCM and the increase in occluded air that it generates in the mortar, as previously mentioned. This argument might explain the increase in resistance between the samples containing 5, 10 and 15% PCM. The voids generated by the first addition of microcapsules are supplemented by increasing numbers of microcapsules as the content increases. This decreases the number of pores, which results in a stronger material. These types of mortars are not designed to withstand mechanical stresses but do maintain their compressive strength within the acceptable range indicated by the regulations [1].

The results of the adhesion test show that the perpendicular tensile strength is stable regardless of the dosage used, even with respect to the standard dosage. As for the Shore C surface hardness, a significant decrease occurs as the PCM dosage increases. This is due to the increase in the amount of occluded air and because increasing the dosage increases the probability that the measurement is performed on an agglomeration of microcapsules.

Using DSC and thermal characterization tests, it was possible to verify that incorporating paraffin microcapsules into the clay mortar is effective. The latent heat increases as the PCM content increases, as expected when the addition is performed correctly. It is 2.87 J/g for the 5% sample in the influence temperature range of the PCM, 5.53 J/g for the 10% sample and 10.59 J/g for the 15% sample.

**References**

2015;**14**(2):44-50

18.06. 2010

561-570

Energy and Buildings. 2016;**111**:393-400

tion. Energy and Buildings. 2008;**40**(3):394-398

Building and Environment. 2013;**61**:93-103

Energy Reviews. 2011;**15**(3):1675-1695

Energy. 2010;**35**(10):2370-2374

storage systems. Renewable Energy. 2016;**88**:526-547

[12] Lane GA. Solar heat storage. Latent heat materials. 1983

[1] Haurie L, Serrano S, Bosch M, Fernandez AI, Cabeza LF. Single layer mortars with microencapsulated PCM: Study of physical and thermal properties, and fire behaviour.

Development of Clay Plasters Containing Thermoregulating Microcapsules for Indoor Walls

http://dx.doi.org/10.5772/intechopen.72410

165

[2] Pérez-Lombard L, Ortiz J, Pout C. A review on buildings energy consumption informa-

[3] Fargallo AP, Alés VF, Rodríguez JM. Comparison of energy-saving restoration costs based on Spain's initial constraints [single-family zone B4]. Revista de la Construcción.

[4] Directive 2010/31/EU of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings (recast). Official Journal of the European Union

[5] Directive 2012/27/EU of the European Parliament and of the Council of 25 October 2012 on energy efficiency, amending Directives 2009/125/EC and 2010/30/EU and repealing

[6] Carabaño R, Hernando SM, Ruiz D, Bedoya C. Life Cycle Assessment (LCA) of building materials for the evaluation of building sustainability: The case of thermal insulation

[7] Kuznik F, Virgone J. Experimental investigation of wallboard containing phase change material: Data for validation of numerical modeling. Energy and Buildings. 2009;**41**(5):

[8] Mandilaras I, Stamatiadou M, Katsourinis D, Zannis G, Founti M. Experimental thermal characterization of a Mediterranean residential building with PCM gypsum board walls.

[9] Navarro L, de Gracia A, Colclough S, Browne M, McCormack SJ, Griffiths P, Cabeza LF. Thermal energy storage in building integrated thermal systems: A review. Part 1. Active

[10] Cabeza LF, Castell A, Barreneche CD, De Gracia A, Fernández AI. Materials used as PCM in thermal energy storage in buildings: A review. Renewable and Sustainable

[11] Memon SA. Phase change materials integrated in building walls: A state of the art

[13] Castellón C, Medrano M, Roca J, Cabeza LF, Navarro ME, Fernández AI, Lázaro A, Zalba B. Effect of microencapsulated phase change material in sandwich panels. Renewable

review. Renewable and Sustainable Energy Reviews. 2014;**31**:870-906

materials. Revista de la Construcción. Journal of Construction. 2017;**16**(1):22-33

Directives 2004/8/EC and 2006/32. Official Journal, L 315. 2012; 1-56

Currently, building simulation software is a fundamental tool for designing buildings with almost zero-energy consumption. In this study, three identical architectural models were simulated. The reference building had inner coatings of clay-based mortar, mortar with 15% added material and a conventional gypsum mortar. These buildings were subjected to the same exposure and radiation conditions, which allowed the result to be compared to evaluate the effect of incorporating the PCM.

Simulations were performed under summer conditions. The results showed that the incorporation of PCM microcapsules into the clay mortar resulted in a decrease of up to 0.5 kWh/m2 (in the simulation period), that is, 10% in the energy required for cooling compared to gypsum mortar. In environmental terms, assuming an emission factor of 0.385 kg of CO2 eq/kWh [34], it would mean a savings of about 25 kg of CO2 equivalent in 15 days. Finally, we affirm that clay mortar allows the incorporation of a PCM without reducing other characteristics that prevent such use. The use of such mortar is more advantageous in summer in climates such as the one at the center of the Iberian Peninsula. This solution will be of great interest for projects involving rehabilitation and improvement in terms of energy efficiency when it is difficult to work on the whole envelope and for small-scale interventions involving interior conditioning.
