One can never answer fully what is the significance of chanting divine names..

We chant the divine name and make nyasa before starting a japa or prayoga.. There is a great and elaborate procedure before performing SriRudra japam.. or abhishekam.. here we praise the deity and sub-deities and invoke their protection of every limb in our body.. This is called mahanyasam. 

One can never answer fully what is the significance of chanting divine names.. ultimately, all human action should boil down to that.. Sravanam, Keerthanam VishnoH smaranam, paadasevanam, archanam vandanam daasyam sakhyam aatmanivedanam.. hearing the praise of the god, praising Him with words, meditating upon him, serving his lotus feet, offering him flowers and other dravyas, prostrating before him, being his unconditional servant, and finally offering oneself Vishnu the Krishna is the quintessence of our relationship with HIM. Nothing is lost by not chanting the divine names during achamanam.. In fact there are occasions prescribed where the achamanm is thuushneem or in silence.. It is said Achyutaandada Govinda Namochchaarana bheshajaad nashyanti sakalaa rogaaH, satyam satya vadaamyaham.. By chanting the names of achyutha anantha and govinda, which is a medicinal spell, all our diseases vanish, it is truth, it is truth.. When the water is taken chanting the achyuta ananda govinda,, the water gets medicinal vallues..we can believe it.

Mahanyasam ..general outline

Mahanyasam ..general outline

Mahanyasam is the ceremonial invocation of lord shiva and his devatas with vedic mantras ..

the lord is invoked in kumbhas or pitchers filled with sacred water etc and also on some mandalas or cluster of materials suitable for invocation of the divine couple shiva and uma .

. In addition the person who chants rudram and chamakam worshipfully invokes the lord and all other gods in various parts of his own body through various nyasa mantrams

This nyasam alone makes him pure and eligible for chanting Sri Rudram.

Namaskaram to the divine couple uma and shankara is offered.

The lords of cardinal points ashtadigpalakas are invoked in the appropriate direction in waterpots or mandalas etc.

The detailed procedure is prescribed by Bodhayana.

The mantras would consume about one and half hours.

If it is not possible to perform mahanyasam a shortened version Laghunyasam is followed.

Nyasam..the word means reverentially and pointedly placing deities..around the main deity in kumbham .

The chanting of rudram is then done honouring the deity invoked in that kumbham.

In addition the deities are placed or invoked in various parts of the body of the one who chants Sri Rudram through anganyasam karanyasam etc.

For nyasa of each deity elaborate vedic mantras and often tantric beeja mantras are chanted.

This is a general outline.

The subject is too vast.

And the procedure can have minor variation according to local practices.

In our nitya pooja with rudram we perform only laghunyasam